If your aim is to buy a book which explains the basics of setting up a Les Paul then this book does achieve this. It also touches in areas of modification and repair. However, for my liking it doesn't really provide enough detail.
The book lists the recommended settings by Gibson for saddle height, pickup height, neck relief, etc but strangely the author doesn't offer any opinions on these settings as even Gibson is referenced as stating that some settings can be subjective - for example pick up height. Another small criticism is that the information for setting up is not all under one section. The neck relief and pick up height is in another section of the book.
The book has some nice illustrations and provides interesting reading on some famous Les Pauls and their owners but I would have liked lots more.