Here's another book that I bought back in the 1990's when I first started coaching youth football for Plano Sports Authority just North of Dallas Texas. My copy of this book is worn out. A ton of good pics and Bass is a great author. You can probably find a good used copy for a bargain.
The book outlines the main position areas in football, like QB, RB, LB, etc and explains their techniques in detail and describes practice drills. You can hit the Amazon link on the left and search inside the book for more details.
I hope you enjoy the book!