“I’m always looking at the couture shows, and Philip Treacy’s hats are completely captivating,” the artist Maira Kalman says, about the headwear at the Spring 2018 Valentino show, in Paris, which inspired this week’s cover. “A painter can’t help but paint them,” Kalman continued. “There’s something about hats that captures all the whimsy and madness of what fashion might be.”