Mr. Lasdun deftly evokes the chill power of cyberstalking. "Spite," he observes, "has never had such an efficient instrument at its disposal." And there is the dread that the infinitely multiplying Internet induces in the targeted victim. "Who else has seen what you have seen?," he writes. "Who believes it? . . . Who has copied it, posted it elsewhere, copied it to a friend?" After all, he concludes, "you are what the Web says you are."