On the presumption that it will mainly be fans of Peter Cook's comedy who pick this book up, I can assure potential readers that you will often laugh out loud at the stream of reproduced work from his long career and anecdotes from his strange life.
More than that though, you get a thoroughly convincing assessment of Cook's long, slow descent into alcoholism (and most other vices you care to name), depression, loneliness, and fear of failure. It is perhaps a testament to 'Cookie' that he could sink so low, and so slowly, and yet remain so loved and admired by anyone, star name or not, who came into contact with him.
It is quite astonishing that a book could be this funny and at the same time so sad. The best biography I've ever read.