This book describes an innovative approach to reflexive game theory. The applications of this theory include predicting and influencing choices made by individual subjects belonging to groups that have their own collective goals and interests. The correlation between a subject's individual interests and those of the group is informed by the anti-selfishness principle: a subject belonging to a group, in pursuing his or her own interests, may not cause harm to the interests of the group as a whole. This principle is as foundational to reflexive game theory as the principle of guaranteed results in classical game theory.