Here's a list of books you can buy pertaning to Case knives.
American Premium Guide to Knives and Razors , 6th EditionThe BEST guide for older Case, Queen, and Remington pocketknives and fixed blade knives, bar none. Also covers the modern Remington Bullet series. Softcover, 504 pp. Author Jim Sargent
This is likely the best book overall to see all of the patterns, handle materials, and tang stamps on the old Case knives. It has tons of pictures from all eras and a price guide that is a bit behind but still a good reference. Counterfeiting Antique Cutlery An essential volume for the collector of antique pocket, hunting, and bowie knives, this book will teach you how to identify and protect yourself from counterfeits. Softcover, 512 pp. Author Gerald Witcher
This is a very through book and a must for any serious old knife collector. However, I would warn the new collector from trying to use this book exculsively. You can learn much more by handling a knife and asking questions in person. Pocket Knife Trader's Price Guide vol. 7. Although this book covers Bulldog, Case Classics, and a few others, it's primarily dedicated to pricing Case knives from the late 1800's up to 2000. 384 pages and authored by the late Jim Parker.
This book is the most current price guide, in book form, today. While some say the prices are high, it is still the most accurate book on the market. In addition, it lists book values for Case knives up through the year 2000 and no other publication is currently providing that. The Case Cutlery Dynasty The extraordinary story of America's oldest and largest family of knife makers, who created some of the most collected knives in the world. Written by Case descendant and award-winning author Brad Lockwood, this hardcover, 304 page book is a must-have for all Case knife fans. Author Brad Lockwood.
I will be adding to this list often, I don't quite have the time to list all of the books at once. I also highly recommend
Knife world as your best source to buy from. I do have a few of them on my web site but Knife World has the best selection