There are several good reference books that I consider essential to the glove collecting hobby.
"The Vintage Baseball Glove Catalog Source Book" collects data from hundreds of sporting goods catalogs, some dating back to the late 1800's. The latest edition has data on over 26,000 glove models from over 500 catalogs.
While the historical record for many of the larger companies (such as Rawlings or Wilson) is nearly complete, much of the information on some of the smaller, more obscure, glove makers has been lost to time.
This book is published by Joe Phillips, and can be purchased through his web site (
http://www.glovecollector.com/ ) or through eBay. Joe is a longtime collector who really got the hobby rolling in the early years, and is also a frequent poster on this board under the user name "softball66".
Joe also publishes a couple of other glove collecting guides- "The Vintage Baseball Glove Pocket Price Guide" and "The Player Autograph Baseball Glove Finder", as well as books about collectible bats and balls.
I use all three of his glove books quite frequently, would consider myself lost in glove collecting hobby without them and highly recommend them to anyone wanting to learn more about the hobby.