The best books on Albert Einstein

Before we start talking about the books, can you give us a brief outline of the significance of Einstein and his work? You’re the author of a biography of Albert Einstein called Einstein: A Hundred Years of Relativity that was republished this year to coincide with the centenary of the theory of general relativity. 

Relativity is generally regarded as his greatest achievement and it comes in two forms: special relativity (1905) and general relativity (1915) — a hundred years ago this month. He also made major contributions to quantum mechanics. He was one of the very earliest to propose the wave-particle duality and probably the first person to do that in quantum theory. He also worked on statistical thermodynamics. He was a pioneer in physics, but, beyond science, he was a genuine contributor to the development of political ideas in the 20th century. He worked very closely with the Zionist movement. He was a great opponent of Nazi Germany and, later, McCarthyism in the United States when he moved there.

There must be literally hundreds of Albert Einstein books. Was it daunting for you to tackle someone of so much significance and interest?

I believe there are about 1700 Albert Einstein books in library files on him and different aspects of him. It was daunting, I think that’s inevitable, but I had some help from experts. The book is mainly a biography but there are contributions from three Nobel Prize winners on different aspects of his life and some other contributions from people in other fields. This collection of shorter pieces is integrated into my text about his life and ideas. My father was a physicist so I grew up with physics and, in fact, my father’s last book was a book for students on special relativity. I can’t claim to understand physics the way my father did — and I think I’m drawn much more to Einstein’s life than I am just to his physics.

And out of those 1700 Albert Einstein books, we’ve asked you to pick just five! Your first choice is Albert Einstein: A Biography by Albrecht Fölsing published in 1997. What makes this biography so good?

It’s comprehensive, for a start. It is a very big book — one of the biggest on Einstein’s life. Fölsing is a physicist by training so he is able to bring clear explanations of the physics into the life. He’s extremely good at quoting Einstein’s writings and comments in an illuminating way. What makes the book unique is that the author is German, when most biographers come from the English-speaking world. He is able to present Einstein’s ambivalence towards Germany both in physics and in politics and bring that to life in quite a subtle way. To have a German writing on Einstein is particularly interesting.

Just to illuminate that, could you briefly sketch the arc of Einstein’s life for us?

He was born in Germany in 1879 and grew up there until he was 16 when he went to join his parents in Italy. He was unhappy with the German educational system: He was not a very willing student in an authoritarian education system. In fact, his whole life was a battle against authority in different forms. Later in life he said—and it’s one of my favourite quotes from him —“To punish me for my contempt for authority, fate has made me an authority myself.” Finally, he was educated in Switzerland and that’s where he really belongs. He kept Swiss nationality throughout his life, until he went to the United States and became an American citizen when he was quite old, in 1940. So, he is not German by nationality, though he was born there.

“He was not very successful in his relationships with his university lecturers.”

The Swiss atmosphere was very productive for his physics, which started in about 1905 with special relativity and some other key work. He stayed in Germany until 1933, when the Nazis came to power, and he had to get out. He spent a little time in Europe, including in Britain in the early 1930s. Finally, he left Europe forever—never to return—in 1933. He lived in Princeton, New Jersey, at the Institute for Advanced Study, a sort of ivory tower. That suited him very well. He could just think and didn’t have to do any teaching. He lived in Princeton right up to his death in 1955. In that period he wasn’t so successful as a physicist — but became much more involved in political causes like the atomic bomb, the hydrogen bomb, pacifism, and Zionism. As a Jew, he was very interested in the founding of Israel and took an active role in that.

One of the most intriguing things about his life story is the fact that when he did his first really significant revolutionary work in physics, he wasn’t working as a physicist was he? He was working in a patent office and didn’t really have contact with other top physicists at the time.

That’s right. That’s always going to be one of the most intriguing aspects of Einstein and his life. He was a patent clerk in Bern and worked in the patent office for a number of years from 1902. After 1909/1910, he finally takes a position as a professional, academic physicist and moves to various institutions around Europe. Probably his most productive years are those years when he was a patent clerk. Having said that, he came up with general relativity when he was a professor of physics in Berlin. Also, at the patent office, although he was not known in the academic world, he had some contact with academic physicists like Max Planck who was a key supporter of relativity. But we should remember that he was always involved with those two worlds.

Are there any clues as to where his revelations came from? Did his unconventional background play a part in that?

Yes. It’s difficult to pin that down but from an early age—from his teens onwards—he was a great believer in self-education. Like many geniuses, he was not particularly successful in his university training. He attended a famous institution—in Zurich—but was always rebelling against his academic education, constantly reading the latest research on his own. He was not working with other people at all. He was not very successful in his relationships with his university lecturers. He was a rebel and, because he was so passionate about physics, his best ideas really came from his own reading and thinking. From his earliest days as a teenager he was a believer in what he called ‘thought experiments.’ He wasn’t involved with laboratories at all, these experiments were all in his head. One of the most famous ones concerns chasing a light ray. When he was 16 or 17, he imagined whether you could catch up with a light ray and what that would mean.

Did that help him to see things that other physicists didn’t, because he was free to think in his own way?

Yes, to begin with, it did. But it’s important to recognise that he was always comparing his ideas with experimental results and, after his miracle year of 1905, attending conferences and involved through correspondence with leading authorities. He did work alone—there’s no question about that—but he also had a lot of sounding boards. He had friends who he tried his ideas out on and often they disagreed—quite violently in some cases—and that improved his thinking. At one point, he did have a collaborator who was a mathematician and they published some work on general relativity together. That’s the only collaborative work that was ever published. Afterwards, he always published alone.

Let’s dig a little bit more into the science with your next choice which is Einstein 1905: The Standard of Greatness by John Rigden from 2005. This Albert Einstein book is about the so-called ‘miraculous’ year. Can you tell us a bit about that?

Einstein published five papers that year. All of them are considered of great value. The paper that Einstein regarded as the most revolutionary of his work in 1905 was actually about quantum theory. There was another paper about Brownian motion. He showed that the phenomenon of Brownian motion—which had been known for almost 100 years—was actually due to atoms bombarding particles. This was considered proof of the atomic theory of matter by his fellow physicists — the first time that atoms had really been proved to exist. Then, the last of the five papers concerned probably the most famous equation in science: E=mc2. This came out of his first paper on relativity and was published at the end of 1905. As everyone knows, E=mc2 is the basis for what happens with nuclear energy and the atomic bomb later in the century.

This is the principle that energy and mass are two aspects of the same thing. So, if you split apart mass, you’re going to release huge amounts of energy which is what drives nuclear energy and the atomic bomb.

Yes, and c is the speed of light. So, with E=mc2, you can immediately see that the amount of energy is enormous from a small amount of matter because c is such a large number. So, E=mc2 implies a very large amount of energy from a small amount of matter through the process of atomic fission and fusion which Einstein didn’t know about in 1905. Fission was not discovered until later — just before the Second World War, in fact.

Let’s talk about the theory of special relativity, then, which was one of the papers in this miraculous year. Can you talk us through that theory?

It’s a response to Newton’s idea of absolute time and absolute space which Einstein rejected after thinking about it deeply. John Rigden puts it quite well in his book. He says, “A world with absolute space existing apart from absolute time would turn into a world where space and time are joined”. This theory of relativity led to the concept of space-time which is a key thought in general relativity. It’s not easy to explain relativity in a few words, but it rejects absolute time and space, leading to the idea that all motion had to be defined relative to a coordinate system — and that different coordinate systems had to be compared. General relativity was much more comprehensive, it included gravitation and acceleration. In fact, Einstein’s great idea about general relativity was that gravitation and acceleration were equivalent and that we must build our idea of the universe on that thought, rather than regarding them as independent, as Newton did.

General relativity is what we often see illustrated with a rubber sheet with marbles on it distorting the sheet. Is that right?

Yes, the curvature of the rubber sheet is a way of expressing—not literally, it’s a symbol—the curvature of space-time. The experimental proof of general relativity came only later. Probably the most famous aspect of the experimental proof is the bending of a light-ray by the gravitational field of the sun. The light emitted by distant stars was observed to be bent by the gravitational field of the sun in 1919 during an astronomical expedition led by Sir Arthur Eddington, a British astronomer. After that expedition, physicists started to take general relativity much more seriously. There were other experimental proofs as well, but that was the beginning of the idea that general relativity was correct. Before that, it was unproven and Einstein asked astronomers to go looking for it. That’s what happened in 1919. Astronomers were able to back up his theory with observations.

So, after we had the proof of general relativity, how was science different? How did the universe look different? What are the implications of that for the way we see the world now?

The whole idea of the Big Bang has been explained, to a great extent, in terms of general relativity. This came much later than Einstein of course — he was dead by then. General relativity also explains the existence of black holes. Einstein didn’t think they existed, but, since the 1960s, experimental proofs have been found that they do. The whole structure of space and time which Newton imagined, an absolute coordinate system, has been abandoned in favour of a curved space-time formulation. That’s really the result of Einstein’s work.

Going back to the miraculous year of 1905, which is the focus of Rigden’s book. His achievements in so many papers in such a short period of time seems almost superhuman. But he was just human, right? Do we risk exaggerating his genius sometimes?

He was certainly very human and had many failings as well as an extraordinary scientific imagination. Scholars have looked closely at what Einstein was doing in the years up to 1905, there’s not enough evidence to be sure. There were a few letters to his wife, and he published a little bit. There is this feeling that it came out of the blue. It obviously didn’t. No genius works from a sudden eureka moment and it’s not like that, even with Einstein. The problem is that we don’t really know exactly what he was reading and how his thought process worked. What we do know is what he published in 1905 and that he was fascinated by contradictions in physics. He imagined chasing a light-ray in his mind and asked what a light-ray would look like if you caught up with it and came to the conclusion that it’s an impossible physical situation. That, according to Maxwell’s laws of electromagnetism, there was no such thing as catching a light-ray. From that, he concluded that light always moves at a constant speed — independent of the coordinate system you were using to measure it with. It didn’t matter how fast an observer moved, light would always move at a constant speed faster than the observer.

“Einstein’s great idea about general relativity was that gravitation and acceleration were equivalent and that we must build our idea of the universe on that thought.”

Another contradiction that fascinated him was to do with magnetism and electric charge. He imagined that if you had a stationary charge observed by a stationary observer, there would be no magnetic field which could be observed with a compass. But, if you kept the stationary charge and then the observer started to move, by Maxwell’s definition of electromagnetism, he/she would observe a magnetic field with a compass. So which was true? Was there a magnetic field or wasn’t there? He said that’s a contradiction, we have to resolve it. And he did resolve it, with his theory of relativity.

There’s often a temptation to move away from contradiction but it sounds like he just confronted it head-on.

Yes, he did. It was fruitful for his imagination. He liked contradictions and found them stimulating. That’s one of the strength of Rigden’s book. With practically no mathematics, he manages to show how various contradictions were perceived by Einstein and then used to create these various papers during that year. Rigden is very good at explaining it in clear language with historical anecdotes nicely integrated into the text.

Let’s talk about your next choice of Albert Einstein books which is the Born-Einstein Letters, 1916-1955, which was republished in 2005. This is a collection of correspondence between Einstein and his friend, the German physicist, Max Born. What do they talk about in the letters?

It was a long friendship. It began with physics but developed into a relationship with many other overtones to do with politics, ethics, and the state of Germany during those years. Both of them won Nobel Prizes, so when we read them we’re exposed to a couple of very intelligent people writing about science. Throughout the letters, you get these human asides: It’s a very unique mixture of science and humanities. They disagreed frequently and they disagreed most famously about quantum theory. In one letter from Einstein to Born he says, ‘The old one does not play dice. I can’t accept the possibility of chance ruling the universe.’ And Born never agreed with that. Right to the end of the correspondence, they’re arguing about the role of probability in physics.

They’re also talking about the First World War and how they react to that and about Jewishness. They’re both Jewish but they have different attitudes to Jewishness. And they’re talking about the Nazi period, of course. During that time, Born escaped from Germany and went to Edinburgh and became a professor. Einstein had gone to the United States — so they didn’t meet. After 1933, they corresponded but they didn’t have any personal contact — which is good, as it means that their ideas are on paper rather than just spoken to each other. We learn a lot. Born edits the letters and has a lot of commentary where he responds after Einstein’s death. Einstein’s step-daughter wrote to him about his last few days in hospital and she said, ‘He left this world without sentimentality or regret.’ Born says, ‘we lost our dearest friend when he died.’ But ‘without sentimentality or regret’ is the keynote of the letters. Einstein can be quite inhuman. He doesn’t have normal human reactions to some things including, for instance, the death of his second wife. His family life was not particularly happy. He divorced his first wife and had a rather difficult relationship with his children. This comes into the book quite a lot because Born is a warmer personality than Einstein. The contrast is interesting.

You say he didn’t have normal human reactions to things. What kind of personality does come across then?

Physics dominated his life. The second aspect that dominated his life was humanity. He had a great passion to support what he regarded as just political causes. He said himself that that was not associated with a love of individuals. He always said, ‘I know I’m quite aloof from the world in relationship to individuals’ — even to Born and some of his other close friends. He didn’t want to rest himself or his life on the ‘merely personal.’ That comes up in an essay when he’s 50. He was very strongly in favour of the idea of world government. After the Second World War, he thought that was the only hope for world peace and to avoid another war. There should be a military-style organisation with the great powers all taking a role in it and preventing war. It didn’t catch on, but he supported that strongly for a while.

Let’s move on to your next choice of Albert Einstein book: The Einstein File by Fred Jerome, published in 2002. This is a book on an investigation of how the FBI, led by J. Edgar Hoover, spied on Einstein for 23 years. What happened exactly?

It started in the 1930s when Einstein moved to the United States. He had extremely mixed feelings about Russia and about communism. He had some sympathies for socialism but he wasn’t a communist. But the FBI and many right-wing Americans thought that he was. So, even after he became an American citizen in 1940, he was regarded with suspicion by them. He wrote a letter to President Roosevelt in 1939 advocating the building of an atomic bomb, along with some other physicists, which was taken seriously by the American government and Roosevelt. Eventually, the Manhattan Project got going, partly out of Einstein’s interest in the subject. Obviously other factors were involved as well, Einstein was not the only influence, but he was quite important. But even though he was involved in supporting this project, he was not allowed to have access to any secret documents. The army, who ran the Manhattan Project, did not give him security clearance. But it seems the FBI didn’t know that and when they started compiling their file in the 1940s, they assumed that Einstein could be a spy with access to secret information about the atomic bomb project and they acted accordingly.

“Long before many people had realised what a risk to world peace Nazi Germany posed, Einstein recognised it.”

J. Edgar Hoover was convinced he was a security risk and might be leaking information to the Russians. When the Klaus Fuchs spy case happened—around 1950—Hoover became even more convinced that Einstein was a risk. But what finally tipped the balance for Hoover was that Einstein gave a broadcast on television in 1950 where he openly told the whole of the United States that the hydrogen bomb, which President Truman had just announced as a project, could cause a poisoning of the atmosphere and would be a total disaster, that it shouldn’t be followed up. Hoover then became passionately convinced that Einstein’s every move should be tracked and that all political associations that he had should be put into this file. He was hoping to prove that Einstein was a communist and that he might be deported from the United States. That was a serious project of the FBI and the immigration service for five years between 1950 and his death in 1955.

And this didn’t come out until reasonably recently then, with freedom of information requests?

It didn’t come out until the 1990s. It’s quite disturbing, really, to think the FBI could have kept the secret for so long. In fact, some FBI agents—even though they were in the employment of the agency—were not aware about this secret file. Hoover knew that if it got out it would cause tremendous embarrassment to the United States government — this world famous scientist being pursued as a potential spy. He managed to keep the secret but how it was kept in the decades after the 1950s and 1960s is extraordinary and quite alarming, I think.

Was this campaign a complete failure? Or is there evidence that it was able to damage Einstein’s reputation or legacy in any way?

Ironically, I think it probably persuaded Einstein—because he was aware he was under surveillance, he didn’t know the details but he knew he was being watched—to come out and make a very public statement in the press in 1953 in support of intellectuals who were standing up against Joseph McCarthy’s campaign. McCarthy reacted very strongly to this and said Einstein was an ‘enemy of America.’ He later changed that to ‘a disloyal American,’ but he never went back on that statement. Einstein thought he might have to go to jail because he was recommending to people that they should not testify to congressional committees about their political views. He said that courage was needed by American intellectuals otherwise they would become slaves. That is what he felt the American government was trying to do during the Red Scare of the 1950s.

It was a very courageous thing to come out and say in that climate.

It was. It is quite moving to read his own private views and worries but he was quite old by then. He was prepared to stand up because he felt the situation had become so like Nazi Germany in the 1930s. He really felt that having lived through the rise of Nazi Germany, he had a duty to warn Americans that the same thing might happen with McCarthyism. I think you can say he was a real factor in the fall of McCarthy. Only one factor, but he was important. After the fall of McCarthy, Hoover realized there was no point in pursuing Einstein anymore. The whole file was wound down by the FBI just before Einstein’s death — but it does run to 1800 pages. One irony is that much of the file consists of associations to which Einstein had lent his name but very little of it consists of his views.

As Fred Jerome points out, if Hoover had been more of a reader of Einstein he would have found much more evidence of his radicalism than by looking at his political associations. But he didn’t do that. He relied entirely on guilt by association and they could never prove, by that method, that Einstein was a security risk, because he wasn’t. He had sympathies that were completely at odds with Hoover’s but he had no access to nuclear secrets and never visited the Soviet Union. Many people did, but Einstein always refused. He was invited many times but he was opposed to many aspects of Stalin and the Soviet regime. People tried to encourage him to go. There was even a false report that he had visited which was used against him by some Americans. But it was a false report. He did not visit the Soviet Union.

Let’s move on to Einstein’s political writings, that Hoover failed to read, in Einstein on Politics edited by David Rowe and Robert Schulmann from 2007. What picture do we get from this Albert Einstein book, then, of his political views?

This is the first book which really collects everything together which is why it’s valuable. There were a couple of books before that but this is the first collection in which everything is there that matters: letters, public statements, all of course in English (many of them were originally in German.) The general attitude has always been that Einstein was politically naïve. I don’t think that’s true. When you see what he did and what he stood for, you can’t call him naïve. He was a committed pacifist until 1933 and made a number of provocative speeches about pacifism. After he recognised what the Nazis stood for, he immediately changed his mind and said that there was no possibility of resisting Nazism without military force. He was prescient. Long before many people had realised what a risk to world peace Nazi Germany posed, Einstein recognised it and argued that the countries of the West would have to arm themselves and fight, eventually.

He was not naïve about Israel. He supported the founding of Israel but persistently said to Israelis that they would have to find an ethical solution to their relationship with the Arabs. Otherwise, the whole state would fail and they had a duty to do so. He never changed his mind and when he was invited to be President of Israel in 1952—not long before his death—he refused saying ‘I have no talent for politics and I would have to say things to my fellow Jews in Israel that they would probably not want to hear about their relationship with the Arabs.’ Again, he was probably right. Whether he could have influenced events more than he did by becoming president, we’ll never know. But he was certainly regarded seriously by the Israelis as a thinker and as an activist. Then, on the matter on world-government, in 1945, it made sense. The United Nations had just started but they were already quarrelling in the Security Council. Einstein said the only way of controlling nationalism was by having a central, military authority. He tried to get both America and the Soviet Union and the British and some other nations involved in that, on the model of the Austro-Hungarian Empire which he had grown up under. He gave a speech at a Nobel Prize winning anniversary dinner in New York, saying, ‘The war is won but the peace is not.’ There was about two or three years of campaigning for world government with other physicists and thinkers. Of course it failed — but that was, I suppose, inevitable in the Cold War.

Is this book just of historical interest, to know what he thought, or do Einstein’s thoughts resonate for us today?

When you read his collected writings, you can’t help but see that there was a connection between his personal integrity and his political views which we all struggle with: how we behave as individuals and how we behave as a collective. His honesty and his courage do make me think. And he wrote well. He had a pungent style, his writing is not woolly, and he had a sense of history too. He also had a wonderful sense of humour. That comes through in virtually everything he writes about politics and human behaviour. Sometimes he was pretty caustic but he was often just gently ironic. I’m sure you’ve seen a photograph at the end of his life of him sticking his tongue out at the photographers. I think impudence and defiance of authority are the defining features of his political statements. I find that, on the whole, admirable.

That is something that seems to run through his scientific thinking and his political views.

He was a rebel, against orthodoxy of all kinds. We haven’t touched on his last 30 years as a physicist which are a bit notorious. He was trying to unify electromagnetism and gravitation — in other words, to extend general relativity to an even more universal understanding of the universe. He didn’t succeed, but in my book I’ve got a piece contributed by Steven Weinberg, the particle physicist, who says that even though Einstein failed we have to admire his determination to carry on and not accept quantum theory as the final theory. He said, ‘I can’t accept that as the final theory of physics, there must be something beyond it.’ He again showed his defiance of orthodoxy because almost every physicist thought he had lost his way. And some of them said so — Bohr, in particular. Niels Bohr came to Princeton in 1939 and Einstein had plenty of opportunity to meet him and talk to his old friend. But he didn’t want to because they disagreed so radically about physics. They spent quite a lot of time ignoring each other. Bohr was very upset about it but Einstein was determined not to reopen this old debate so kept his distance.

How should we remember Einstein?

As a unique genius. I’ve written two books on genius and I can’t think of anybody else who managed to combine science and decent human behaviour in the way that he did. And also as a humorous man. I really admire his jokes…