A First Course in String Theory
by Barton Zwiebach
This is a book by my MIT colleague Barton Zwiebach, and it grew out of a year-long course that he taught at MIT for undergraduates who wanted to learn string theory. So he goes through a lot of the material. He does it without any claims of completeness, but you really do get the idea. Of all the books I’ve mentioned, this one is the most direct route into the heart of the subject.
