IT’S a miracle. That’s what the humans believe, more often than not, after watching this compact, 40-year-old C.E.O. do his work. He enters a room purposefully, his chest thrust forward and a smile on his face. “How can I help?” is his standard introduction, and the way he says it — calmly, assertively — indicates that your problems are about to be solved. It’s unbelievable. That’s what the humans say when they see what Cesar Millan, the “Dog Whisperer,” can do. And the dogs? To a pooch, they appear to be thinking: “Thank God, help has finally arrived.” To prompt...