Leathercraft Tools by Al Stohlman - best book in my collection.
If you are going to dive into leatherworking, I would advise you to get a head knife. This is probably, my most used tool for cutting, skiving, trimming, etc... The Leathercraft Tools book will show you how to use it, sharpen it, and maintain it. There is no other tool in that book that is explained in more detail than the head knife, and my belief is that Al wanted to show how important this tool was to the leather industry. I personally have an osborne round knife, an al stohlman brand head knife (both from tandy) and a danny marlin head knife (my favorite). I bought i directly from danny, but I think hidecrafters still carries danny's knives.
Also, find and buy a good swivel knife. Hopefully you can attend some shows and get to hold them in your hand and test drive them.
Marlon