William Koehler had served as principal trainer at the War Dog Training Center, in California, and after the war became chief trainer for the Orange Empire Dog Club at the time the largest dog club in the United States, instructor for a number of breed clubs, and a dog trainer for the Walt Disney Studios.
In 1962 Koehler published The Koehler Method of Dog Training in which he is highly critical of what he calls "tid-bit training techniques" based in "the prattle of 'dog psychologists'". Amongst the training innovations attributed to Koehler is the use of a long line in conjunction with a complete absence of oral communication as a way of instilling attentiveness prior to any leash training. Koehler insisted that participants in his training classes used "emphatic corrections", including "explosive" leash jerks, throw chains, slingshots, and high level electric shocks, explaining that tentative, nagging corrections were cruel in that they caused emotional disturbance to the dog.
Koehler also suggested spanking, striking the dog with a rubber covered dowel on the muzzle, and suspending dogs off the ground with a choke collar as punishments for various behaviors.
The content of the book has led to it being banned in Arizona for a time. Despite the controversy, his basic method forms the core of many contemporary training systems and has had a heavy influence on many others.