The biggest picture on the wall of my home office is not of my wife or daughter, or our parents, or any other relative. It is of a now long-gone but still cherished member of our family—our first dog. Murphy was a brown and white, thirty-pound Sheltie my wife and I adopted a few years after we married. He was, before our daughter was born, our first “child.” He was a thoroughly lovable dog. Sharp as a tack—I taught him to sit and shake in about ten minutes—an endless source of delight in games of fetch, and great company—most of the time. He was also an incorrigible chowhound, forcing us to guard our food zealously at mealtimes. He exploded into fits of barking and jumping whenever we had guests or if he saw a bicyclist, car, or dog on our walks. We tolerated it all, not knowing that it might be possible to change those behaviors. We figured it was a small price for living with a wonderful dog.