THE STORY OF HOW TYLER decided to leave the mountain is a strange one, full of gaps and twists. It begins with Tyler himself, with the bizarre fact of him. It happens sometimes in families: one child who doesn’t fit, whose rhythm is off, whose meter is set to the wrong tune. In our family, that was Tyler. He was waltzing while the rest of us hopped a jig; he was deaf to the raucous music of our lives, and we were deaf to the serene polyphony of his.