Betcha get a lot of different responses on this one.
I'd say "Turkey Hunters Digest" by Dwain Bland as #1.
Then there are several others which are really good:
"Turkey Season" an Outdoor Life compilation
"Spring Gobbler Fever" by Michael Hanback
"Hunting America's Wild Turkey" by Toby Bridges
Seems like a lot of the books contain information that is more pertinent to hunting in the South and Midwest which makes sense because these are traditional turkey areas. However, there is growing interest in hunting turkeys in the west, both by those of us who live here and by others who are interested in traveling here. . . . a new book on contemporary turkey hunting in the west would be dynamite if the right author took the lead.
Just my 2 cents.