by The Bee Gees
This is nice biography written by nice people about a group of nice guys. If you are a fan, you will love it. If you're looking for an analytically sharp look at the Bee Gees' contributions to music history, that book has not yet been written.
If you are interested more in disco from an historical and sociological point of view, read this book from American Studies professor and Janis Joplin biographer Alice Echols.