One of my favorite places to find good dog related books, is Dogwise.com. You can also get on their email mailing list and get notices of sales and great deals on books, as well as streaming videos.
I also like to shop Smile Amazon, to support my favorite charities. Amazon products rarely disappoint, and shipping is always excellent. I have found numerous dog related books on Amazon, that account for most of my library. I also have found a few dog products that I use in our daily training exercises and search missions.