Let’s say Bob only gets to read ONE book in their lifetime – which ONE book are you recommending to Bob?

A silly hypothetical, but I want to hear which book you think is worthy for it to be the ONLY book that Bob gets to read.

(this is for fun, you don't have to participate if you don't like the hypothetical, but I am trying to see what are the best books in the world in your opinion) Thanks in advance!