Also on Allen’s bookshelf is the wacky 1972 volume “Underground Interiors: Decorating for Alternative Lifestyles,” which he bought on a tip from Murray Moss during a period when he was collecting obscure design books. “It documents this period in wild interiors that are oddly unfinished and poorly detailed, but exuberant and really fun,” he says. “The page pictured here is Karl Lagerfeld’s apartment. There’s also one where everything in the apartment is covered with sheep’s fleece — they were chosen for their oddity.”