This is a great book. Oliver Sacks is a neurologist/author most known for his two collection of case studies titled "The Man Who Mistook His Wife for a Hat", and "Awakenings" which was made into a great movie with Robin Williams and Robert DeNiro. His books are completely accessible and meant for laypeople, and are some of the most fascinating books I've ever read.
Musicophilia is all about how our brains process music, musical "disorders", and some of the more interesting - and sometimes disturbing - things music can do to our brains. I'm only 150 or so pages into it, and am in awe at the power of music on a purely physiological level. In those 150 pages, he's already discussed musical hallucinations, the lesser known side effects of acquired deafness in trained musicians, perfect and relative pitch, and the recreation of stereo sound with one ear!
I'd say that anyone who has ever sat back in ecstasy during Chopin or Hendrix (and who likes to read) owes it to themself to check out this book. Already, music seems that much more mysterious because of what I've read.
EDITED TO ADD: here's a link to the NYTimes review:
http://www.nytimes.com/2007/11/20/books/20kaku.html?ref=booksEDITED AGAIN FOR A MORE INTELLIGIBLE POST TITLE
