Mark is wonderful, kind, patient, and yet firm. Our 4 month old German Shepherd puppy was out of control when we would try to bring him inside to sit with us. He would bite us, jump on us, and was so difficult. He could only last for about 10 minutes and we would have to put him back in his crate. One session with Mark, and now he sits on his bed calmly in the house, for up to an hour! It’s like a different dog. What a difference! Thank you Mark!