The Psychopath Test is good, but I enjoyed his other books even more: Them and (despite the crappy movie they made of it) The Men Who Stare at Goats. Psychopath has a lot of interesting stuff in it and I would never suggest anyone not read it, but his perpetually second-guessing, tends-to-believe-the-last-thing-he-heard persona frustrated me after a while in a way that doesn't become so onerous in the earlier books.