Advances in artificial intelligence pose a myriad of ethical questions, but the most incisive thinking on this subject says more about humans than it does about machines, says Paula Boddington, philosopher and author of a recent AI ethics textbook. We first spoke to Paula in 2017—a long time ago in a fast-moving field. This week we caught up with her to find out what's happened since then and which new books have taken the conversation over ethics and AI further.

'Big history' looks at history on the timescale of the Earth and the universe, rather than just the short period of time that humanity has been around. Here, Toby Ord, a moral philosopher at Oxford University's Future of Humanity Institute, recommends books to get a handle on it, and explains why now is a critical time for Homo sapiens.

In the rapidly-emerging field of existential risks, researchers study the mitigation of threats that could lead to human extinction or civilisational collapse. We met with four researchers from The Centre for the Study of Existential Risk at the University of Cambridge, to discuss their recommendations of the best books to get a grasp of this dense subject.

If killing is wrong, how can going to war be justified? Is it always wrong to kill civilians? If a Nazi soldier were billeted in your home, should you respond when he greets you? Philosopher Cécile Fabre chooses Five Books that help explore the profound ethical dilemmas of war.

Zombies have returned with a vengeance in recent years, the secret to their undying popularity lying in their ability to embody many different kinds of menace, from social unrest to pandemics, financial insecurity to international terrorism. Greg Garrett, author of Living with the Living Dead, recommends five books to help you prepare for the zombie apocalypse

The introduction of drones "makes possible perpetual war without costs", warns the anthropology professor and security expert Hugh Gusterson. Here he selects the best books that examine their ethical, psychological and political impact upon 21st century warfare.

Public understanding of radiation needs to improve if people are to properly assess its benefits and risks argues author and academic, Timothy Jorgensen. From the discovery of radio to a cancer cluster in New Jersey, he chooses highly readable books illuminating different aspects of radiation.

What will the next global conflict look like? Two of America's leading defence experts, P W Singer and August Cole, turned to science fiction to explore the prospect of a future war, and how existing technology might be used in one. Here, they choose five novels depicting a fictional World War Three that served as inspiration.

It could lead us all to immortality or spell the end of the human race. Author Calum Chace picks the best books on Artificial Intelligence or AI.

Evolutionary biologist Beth Shapiro tells us why it's impossible to clone a mammoth, and why we might want to. She guides us through five inspiring books to get us thinking about extinction and the role genetics could potentially play in maintaining biodiversity.