And Jack finally understood that the greatest privilege of being loved was not the power it gave him over another person’s heart, but the duty it placed upon his own.… When Jack first met Clara, he believed that love was the simplest thing in the world. It was a rainy afternoon in October when they encountered each other in a small bookshop tucked away on a quiet street in London. Clara was standing near the window, holding a book of poetry, while Jack was searching for a novel he had been meaning to read for years. Their hands reached for the same book. She smiled. He apologized. They laughed. It was an ordinary moment, but something about it remained with Jack long after he had left the shop. Clara was thirty-four, a landscape architect with an unusual sensitivity to the emotions of others. She had been married once, and the experience had taught her that love was not necessarily measured by the intensity of one’s feelings. Sometimes, she explained, the gre...