'I find that when I am in the dog runs, I am nearly invisible to my subjects. . . They play like little boys throwing one another down a hill on the school playground. They practice in their play what nature has said they must know. Dominance, defense, breeding and agility. And I am often nearly on top of the dogs in useful obscurity, making the first pictures of my life that actually make me laugh.' Internationally renowned photographer Michael Crouser...