Those looking for an emotionally reassuring answer to the title's age-old question would do well to avoid Gelven's circuitous, scholarly discussion of the role fate plays in people's lives: the Northern Illinois Univ. philosophy professor prefers to dwell on the loftier ``why'' while shunning the more compelling implications of ``me.'' Rare are those who fail to wonder, in moments of extreme good fortune or tragedy, why they were personally fated to enjoy or endure these particular twist of fates. The question of ``Why me?'' arises potent issues of uncontrollable destiny versus free will, random chance versus inevitability, and moral responsibility versus guiltlessness. In first examining the more basic question ``Who am `I'?,'' Gelven emerges with the intriguing premise that ``I'' cannot exist without fate because the events that happen to a person decide the story of his or her life, defining the person as walls define a room. Without such a story constructed by fate (and involving an interplay between destiny and free will), human lives are as unconnected and meaningless as those of beasts. It is our fate, triumphant or tragic, that gives existence its essential meaning. The title's question, then, could be answered in this way: ``Because as the person to which these events have occurred, I matter''--hardly satisfying to those in one of fate's tighter clutches but intellectually stimulating nonetheless. Highly cerebral despite Gelven's use of lay language.