I have two really good applique books.
Applique Made Easy - Rodale -It's a book filled with techniques and shows how to do them step by step in pictures.
1001 Full-Size Patterns, Projects & Ideas - Better Homes & Gardens. I use this book mainly for patterns, not techniques.
I found the BH&G book in a large bookstore, and my son got it for me through the internet for a fraction of the cost.