Genius: Richard Feynman and Modern Physics by James Gleick (1994)

This is a good book.

It has some overlap with Surely You're Joking, Mr. Feynman, which it likely takes as primary sources of some stories.

However, while Surely goes into a lot of detail of each event, this book paints a more cohesive and global picture of things.

In terms of hard physics/mathematics, this book takes the approach of spending a few paragraphs in some chapters describing in high level terms some of the key ideas, which is a good compromise. It does sometime fall into the sin of to talk about something without giving the real name to not scare off the audience, but it does give a lot of names, notably it talks a lot about Lagrangian mechanics. And it goes into more details than Surely in any case.