“Mating in Captivity” (2006), the book that brought her to public notice, was a sprightly disquisition on the anaphrodisiac effects of married life, in which she argued that the excessive value placed on communication and transparency in modern relationships tends to foster conjugal coziness at the expense of erotic vitality. Her suggestion that couples seeking to sustain their élan vital would do well to cultivate a little distance and mystery was not original, or particularly radical, but it inspired wariness and even hostility among some of her colleagues, who felt that she approached the solemn project of saving American marriages with insufficient reverence.