If you read popular books on neuroscience (like those by Oliver Sacks or V. S. Ramachandran or David Eagleman), you will have encountered many of the types of case studies presented in The Man Who Wasn't There.

So, there's not a lot of new material here in this book that focuses on trying to answer the question "What is the self?" by examining how various neurological disorders and dysfunctions affect the sense of self.

The chapter on epilepsy, though, did present some material that I had not previously encountered, especially in regards to the feeling of oneness with the universe and where in the brain this feeling originates, so I found this chapter particularly fascinating.

The epilogue was also very good, presenting an overall synthesis of not just the cases examined previously in the book but also the broader philosophical arguments about the self. Ultimately, the author does not tell us what he believes to be the definitive answer to the question posed in his book, though he seems to hint at believing in some sort of minimal, pre-linguistic self that serves as the subject for experience even in those who are experiencing a loss of their sense of self.