An "affecting tale" of a romantic reunion and a midlife affair from the New York Times–bestselling author of The Pilot's Wife (Publishers Weekly). Out of the blue, Siân Richards receives a letter from her first love, a boy she met at summer camp—and she sees no reason why she can't write back to Charles Callahan. After all, it's been thirty years and they are both married with families. But when they decide to meet again, an innocent correspondence becomes a dangerous intimacy. Swept up in the past and consumed by an obsessive love, Charles and Siân risk everything to be together. A heart-wrenching, suspenseful story with an unforgettable conclusion, Where or When is also a "thoughtful, beautifully written contemporary romance" from the acclaimed author of The Stars are Fire and The Weight of Water (The Washington Post). "Who hasn't dreamed about reuniting with one's first love? Where or When indulges the fantasy, then sets it afire . . . A seductive read." —Vogue