This took me three weeks to read, which is not a criticism, just that, as a popular science book it contains a lot on which to reflect. Pieces of Light focuses on personal episodic memory, specifically on the current theory that we actively construct a memory narrative, each time we recall a past event. Charles Fernyhough skilfully blends interesting and entertaining personal anecdotes with sound scientific principles to explain this central idea. He explores the memories of both the very old and the very young and even literary characters such as Thomas Cromwell in Wolf Hall (would-be authors take note of the value in creating a convincing memory for a central character!). He also examines the effects of disease, trauma and amnesia.
This is a fascinating and surprisingly literary study of how we remember and importantly, how we forget. I would hesitate to recommend it for book groups because I suspect it would take too long to read, but it would be an excellent starting point for a discussion.