Having myself grown up in Berkeley, where Nobel laureates are a dime a dozen, I certainly know the syndrome: the mismatched socks, the spectacles repaired with duct tape, the forgotten anniversaries and missed appointments, the valise left absentmindedly on the park bench. Yet hometown experience did not prepare me completely for Dyson. In my interviews with the physicist, he would sometimes depart the conversation mid-sentence, his face vacant for a minute or two while he followed some intricate thought or polished an equation, and then he would return to complete the sentence as if he had never been away. I have observed similar departures in other deep thinkers, but never for nearly so long.