I would really recommend "Turkey Hunter's Tool Kit: Shooting Savvy" by Jay Langston. It was written several years ago but the information in it is still very useful. You'll also get some history of shotshells, shotguns and read about some of the real pioneers in the modern turkey hunting age.
I consider it a vital part of my reference library.
I understand that you can order that book directly from Jay. It would be money well spent!
P.S. There are also several excellent books available here from the folks at T&TH.
"If he's out of range, it just means that he has another day and so do you."