Mark was AWESOME! I rescued a chi-terrier in January, she was super timid and not "the best listener." After ONE class with Mark, she could sit, stay and even stay long enough for me to let a stranger in the door. She had MAJOR Stranger Danger anxiety before we started training. Five weeks later, she's like a different dog, she is so much more relaxed and even walks off leash now. Mark has a great demeanor and really knows his stuff. I would recommend Mark to anyone who loves their puppy and needs help.