Some perfectly wonderful trainers have no official accreditation; while trainers with wonderful letters after their name are not very good with either dogs or people. (connieswaimcaninebehaviorservices.com)
These books have been just as important as the help of two wonderful trainers in changing how I communicate with my dog so that he learns what I'm asking for, I learn what he's asking for, and we all live happily ever after. (mnn.com)