I bought this for a neighbor who was "training" his new dog by tethering it to the leg of his trampoline in the back yard so tightly that the dog couldn't even stand up all the way. The guy left him alone out there for a few hours, and I heard such pitiful, desperate barking and crying from a block away. Long story short, this guy was told by a gun dog trainer at the Dixie Deer Classic expo at the NC State fairgrounds that this was the way to train the dog to "come." Umm, what???
It's long, long, long overdue for us to start using positive reinforcement training methods for our companion animals, whether it be horses, dogs, goldfish, whales, lions, or amoebas. I'm an animal-loving treehugger, but most of my friends are grumpy ol' rednecks who hunt and fish, and I think we'd all agree on this.
If you were taught to train dogs using traditional methods, you may want to buy a couple other more general positive-reinforcement books along with this one. No clicker necessary; you can use a short word or a sound just as easily. The "click" or word is just a marker pinpointing the precise moment when the dog started doing what you want him to do, so he remembers why you're rewarding him in the long moments it takes you to dig a treat out of your pocket!
A couple other really great books: "Don't Shoot the Dog" by Karen Pryor, "How Dogs Think" by Stanley Coren, and "The Other End of the Leash" by Patricia McConnell. If you read all three of these books, your dog won't just be a gun dog; he'll be a superhero! More to the point, he'll think *you're* a superhero!
Oh, and also, it'll really impress your gun-dog friends when you can do things with your dog that they could never do with theirs. And then when you do it with *their* dogs too!