He doesn't much like doing these things, but he does them all the same. Bill Petit arrives at the high school alone and walks up the knoll from the parking lot, squinting against the low, late-winter sun. It's chilly, and he walks with his hands shoved into the pockets of his jeans. He wears his hair, damp from the shower, combed straight back into a fringe of curls that sweep the collar of his baggy white golf shirt. He stands six foot four, sturdy and thick, with the belly of a man who hit fifty a few years ago pulling slightly at his fleece vest. Across the lot behind him, suburban Saturday-morning traffic drifts up Main Street. Above, under a dry blue Connecticut sky, two swallows chase each other around the sun. The man walks slowly — he always gets a little queasy at these benefits, as the people are coming just for him and he is required to be social. Being social has never come easy for him, but now it can be excruciating. Outside the doors, one of those inflatable castles for kids to jump around in is set up on the sidewalk. He stops.

A boy, four years old, blue-eyed and sandy-haired, sits on the ground. Not many people are around yet — it's nine-thirty, and the basketball tournament doesn't start until ten. The boy is unstrapping the Velcro on his shoes and jimmying them off his little feet. Bill Petit bends at the waist with his hands on his knees.

"Hey there," he says to the boy. He arches his eyebrows hopefully and holds up a hand for a high five. The man's cheekbones are high and wide, like rock faces. The boy looks up at the giant hand but quickly scrambles into the inflatable castle. Petit stands up straight again. "Ah, he doesn't want to talk to me," he says, his voice deep and rusty and the words rattling out unevenly, as if they are the first he's spoken since waking up. "He wants to play." He drops his jaw a little and laughs to himself, then turns and wanders into the school.

This work — the work of his foundation, which he establ...