“Overall, this is a well-written, easily comprehensible collection of typological (epidemiological) investigations into “altruism’s gloomy underbelly” (p. 7)asserting that “some people are pathological altruists in their essence” (Krueger, p. 298). From its seemingly oxymoronic title to the final chapter, the content flows logically in a coherent, clear, and convincing presentation of all aspects of altruism. Ultimately, the book adds to the growing scientific examination of empathy and prosocial behavior. It is a must read for clinicians and researchers interested in these fields.”