Sometimes you feel euphoric. Everything is sublime and has an aura, and suddenly you are intensely nauseated and then you are gone. You are throwing up on some suburban geraniums, or your father’s tennis shoes, or your very own bathroom floor three days ago, or a wooden sidewalk in Oak Park, Illinois, circa 1903, or a tennis court on a fine autumn day in the 1950s, or your own naked feet in a wide variety of times and places.

　How does it feel?

　It feels exactly like one of those dreams in which you suddenly realize that you have to take a test you haven’t studied for and you aren’t wearing any clothes. And you’ve left your wallet at home.

　When I am out there, in time, I am inverted, changed into a desperate version of myself. I become a thief, a vagrant, an animal who runs and hides. I startle old women and amaze children. I am a trick, an illusion of the highest order, so incredible that I am actually true.

　Is there a logic, a rule to all this coming and going, all this dislocation? Is there a way to stay put, to embrace the present with every cell? I don’t know. There are clues; as with any disease there are patterns, possibilities. Exhaustion, loud noises, stress, standing up suddenly, flashing light—any of these can trigger an episode. But: I can be reading the Sunday Times, coffee in hand and Clare dozing beside me on our bed and suddenly I’m in 1976 watching my thirteen-year-old self mow my grandparents’ lawn. Some of these episodes last only moments; it’s like listening to a car radio that’s having trouble holding on to a station.