One autumn a few years before he died, my father came to visit. I was in my forties and freshly married, a poet who had just begun a family. My father, a veteran of the Second World War who had survived into his eighties, had driven with my mother a thousand miles from Virginia to Illinois to see the first of his three grandchildren. The birth of a child should be a perfectly joyful and unblemished occasion, and indeed there was much laughter and celebration that week in our house. But the depression and hopelessness that had dogged me since childhood had recurred, and I was struggling to keep my balance.