“Do you believe in past lives?” asked Sally Snowman. I hesitated, and she changed the subject. Later, she mentioned it again. “When I asked you about past lives,” she said, “I feel as if I’ve done this before, and that I came home. For the past 17 years, Snowman has served as the keeper of Boston Light, a centuries-old lighthouse, out on a freckle of treeless land in Boston Harbor, in Massachusetts. It’s a lifelong love story—at 10, she first visited the island with her father. “I stepped out of…
