As a Christopher Guest fan, I was really excited to read this book. Waiting For Guffman is my favorite movie, so I was fully expecting to love this book. However, I could not stand the author's writing style. So, I give the content a '5' and the writing style a '1.'
It would be best if you have seen Guest's 4 biggest films: This is Spinal Tap, Waiting for Guffman, Best In Show, and A Mighty Wind. There are major chapters on each of these movies. I really enjoyed learning facts about the making of these movies. I also enjoyed the interviews with Fred Willard, Deborah Theaker, and others.
My large problem with the book was the way it was written. Muir goes into editorializing a lot in a needless way. He calls A Mighty Wind Guest's best film, and even though he makes his case, it seems out of place. I also cannot stand how he starts acting too familiar with the interviewees. He calls Deborah Theaker "Deb" in a couple places and mentions one interviewee's current movie (a Hillary Duff project that no Guest fan would possibly care about). He also makes a factual error in talking about Guffman and spells Teri Hatcher's name wrong. The author also draws on conjecture in a few places and seems to presume too much when talking about some of the editing or directing or writing choices.
I would recommend this book for truly diehard Guest fans only.