The Echo Maker, by Richard Powers

A man suffers severe head trauma and wakes up from a coma convinced those around him aren’t who they claim to be. His sister moves to take care of him and must cope with his denial of her identity. A famous psychiatrist addresses the case and has a breakdown while doing so.

Lives come together and break apart, while notions of reality, sanity and identity are questioned. An interesting book that makes you think. Plus, you don’t really end up liking any of the characters which is refreshing.