The first book I bought on horse training was "There Are No Problem Horses, Only Problem Riders" by Mary Twelveponies. Then I bought "Lyons On Horses" by John Lyons. Then I subscribed to Lyons' "Perfect Horse" magazine. Then I attended a community ed horse training class. Then I bought "You Can Train Your Horse to Do Anything!: "On Target" Training -- Clicker Training and Beyond" by Shawna Karrasch. I've skimmed Pat Parelli's stuff. I've seen Monty Roberts on DVD and in person. I've seen John Lyons' video series. Just so you know where I'm coming from.
The only purchase I regret is the Mary Twelveponies book. I can't think of a single solution in her book that isn't better solved by the others, and some of her advice is questionable. Lyons is great, but spend your money on his magazine instead of his book. Clicker training is very useful (I solved a bridling problem in one day after reading the book) but Karrasch wastes many pages prattling on about the science of operant conditioning. I read B.F. Skinner is college; I didn't need the history lesson. She does the same thing in the related video -- exceedingly disappointing. Monty Roberts can do anything as long as he has enough panels and mechanical contraptions and a big strong gentle well-trained saddle horse to work alongside the horse he is training. If his ego and use of terms like "Join-Up" and "Language of Equus" doesn't put you off, you can learn a lot from Roberts. Parelli always seems to be having more fun with his horses than anybody else, but I can't figure out what he's doing half the time. (see update on Parelli, bottom)
Which brings us to Clinton Anderson. What I especially appreciate about his approach is its effectiveness. Anderson excels in two areas: his techniques give rapid results and he is an exceptional communicator. Most of his clinics are not the standard get-a-green-horse-in-the-round-pen-and-be-on-him-by-the-end-of-the-day. Instead, he works with riders who are having problems with their horses, and teaches the riders to be trainers rather than doing the work for them. That approach has helped him refine his techniques and appreciate all the ways we are likely to apply them incorrectly.
For the book, Anderson recruited two riders with problem horses and put them through his program. Each chapter describes the technique, its purpose, how to apply it, how to deal with bad reactions from the horse and mistakes from the rider. It was especially helpful to read the comments from the two women on how their horses reacted and how they had to overcome their own mistakes.
I've only done one session with my horse and the results were dramatic enough to make a believer out of me.
For a sample of his techniques go to his web site, scroll down to the bottom, and click on articles. There's some good stuff there that isn't in the book.
If you have a horse that doesn't always know what you want or won't always do it, or you're a little afraid of it, this is the best book I've found. I highly recommend it.
Last summer I attended a Pat Parelli 2-day seminar, and since then I've had the opportunity to review his Level 1 and Level 2 instruction material. There is an amazing degree of agreement in Clinton Anderson's and Pat Parelli's techniques. Both stress ground work on a long lead using a rope halter and a stick with a string, Parelli's 7 games all have counterparts in Anderson's techniques, both stress riding with reins on the saddle in an enclosed area to develop a good seat, both stress the importance of starting with the lightest possible touch and being willing to escalate to whatever it takes to achieve the desired behavior, and countless other similarities.
Where the two differ is that Anderson is all efficiency and maximum results in the least possible time, which is why he won the Road to the Horse colt starting competition 2 year's running. Parelli wants you to get into your horse's head, develop a relationship with him, and come up with training exercises that keep him interested. Advance in Parelli's program and you'll be able to direct your horse over a jump from a hundred feet away (could be just the thing if your horse gets out -- just get his attention and send him back over the fence.)
Seriously, these two celebrity trainers have highly complementary techniques. I found the Parelli seminar helpful and inspiring, and I think Parelli fans would have the same reaction to a Clinton Anderson seminar. I think Parelli fans would find Downunder Horsemanship to be a helpful supplement to the materials they already have, and I think readers of Downunder Horsemanship would profit from seeing Parelli demonstrate his techniques