This is a frustrating book, but it couldn't be any other way. Most other popular science writing is about questions answered, perhaps with a few unknowns left over.

This book, about how we perceive music, is about mysteries with no real explanation. Sacks' writing style doesn't help matters; he opts for the atheist-mystical prose style all too popular in this genre: meditative, introspective, it rapidly becomes the literary equivalent of listening to Coldplay on repeat, made worse by his tic of describing all his male patients as ‘eminent' and all his female ones as ‘gifted'.

Musicophilia begins by asking why humans are the way we are. What is the point of humans being evolved to be interested in music? Why is it so important to us? Why do tunes get stuck in people's heads, when photographs and paintings just don't? Why is our processing of speech and sound so separate, so people who cannot speak due to a stroke can sing perfectly, or can understand speech but hear music as a cacophony?

Theories exist, and Sacks mentions them, but the main focus of the book is a series of case studies, which show how abnormalities can throw a little light on how our minds perceive music. All different, many terrifying (imagine being unable to stop hearing music in your mind), their bare facts alone give tantalising hints of how brains work.

Brain damage can suddenly give people a talent for music they did not have before; mescaline can make emotional music overpowering but destroy perception of classical music's structure; amnesia victims unable to remember anything for more than a few seconds can conduct a choir perfectly.

Ultimately, the fascination, scope, and sheer strangeness of the book's subjects transcend its flaws: Musicophilia gives a real sense of where science might go next, and how little we understand of what goes on inside our heads. Big mysteries, frustrating though they might be, are fascinating in a way a small answer can't hope to match.

Four stars