When I read that someone had written a book documenting EVERY formula used in Excel, I didn't believe it. First of all, who has that kind of time? Secondly, Why?
When I first received the book and attempted to thumb through it, I was AMAZED. The book is not only comprehensive in its coverage of ALL THE FORMULAS, but also includes highly detailed explanations (including examples) of all the formulas and functions included in the program.
I do not envision anyone actually sitting down to read this entire book, but as a reference for ANYone who finds themselves looking for a quick reference to better understand some of the extended functionality of Excel, I think this book is invaluable.