I have no idea why this edition of Duchossoir's work is still in print. His update to this book is "Gibson Electrics - The Classic Years." "Classic Years" is a much better book with much more information. It's better organized and it has much more in the way of B&W and color photos. It's an excellent resource.
This 1981 volume is a good piece of work, but it's incomplete. Duchossoir originally conceived of a two volume work covering the history of every Gibson electric model from the first lap steel guitars that Gibson produced in the early 1930s through the "Norlin" era (Gibson was still owned by Norlin when this book came out). He ran out of steam after finishing this volume and Volume II never came out. The updated book is MUCH better and you should spend your dollars on that book rather than this one.
If you are a die hard guitar enthusiast/collector you will find this book helpful and it does cover some areas and have some good photos of hard to find instruments that are not included in the updated "Classic Years" book so it's not a bad idea to grab both books if you're a died in the wool Gibson nut (like I am). If you're a casual reader/collector get the newer edition.