Solitude is a recurring theme in Pape’s photos, which isn’t to say that it can’t be shared. At the 110th Street branch of Animal Care Centers of N.Y.C., one of the city’s largest rescue shelters, the technician Tai Welcome spends a quiet moment with a kitten just after midnight. The night shift is a time for shelter employees to catch up on new intakes, giving each animal a physical exam and a dose of dewormer. Over at the center for sleep disorders at N.Y.U. Langone, Christy Day applies electrodes to a patient, preparing to monitor his brain waves, respiratory patterns, limb movement, and blood-oxygen level throughout the night. She has worked as a sleep technician for fourteen years, helping the restless find slumber at the expense of her own. A night volunteer at the Samaritans suicide-prevention center, in midtown, pursues a similar mission, offering solace in the form of conversation and a friendly ear to those who call the twenty-four-hour hotline after dark.

Leo De St Aubin, a vender for Lockwood & Winant Seafood at Fulton Fish Market, Hunts Point, the Bronx, 2016. Catherine Rodriguez, a server at Resorts World Casino New York City, Jamaica, Queens, 2016.

Some people seek out late-night work for its transformational possibilities. Cesar Villavicencio, who performs six nights a week at Therapy, a bar in Hell’s Kitchen, begins putting on makeup at home around eight in the evening and is onstage two and a half hours later, strutting in front of a crowd as the drag queen Pixie Aventura. Others happen upon their odd hours by chance. Leo De St Aubin trained as a carpenter but got into the fish business after he was injured on the job. He’s worked as a fish salesman for thirty-five years, twenty-six of them at the seafood wholesaler Lockwood & Winant, carpooling to the all-night Fulton Fish Market from his home in Smithtown, Long Island. When the market was still in lower Manhattan, he told me, the hours were later, and easier to manage. He got to work around two o’clock, and was home by ten or eleven to catch a few hours of sleep before taking his kids to Little League games and soccer practice, getting in a second nap in the early evening, before the next shift.