Most developmental psychologists agree that what differentiates one leader from another is not so much philosophy of leadership, personality, or style of management. Rather, it's internal "action logic"--how a leader interprets the surroundings and reacts when his or her power or safety is challenged. Relatively few leaders, however, try to understand their action logic, and fewer still have explored the possibility of changing it. They should, because leaders who undertake this voyage of personal understanding and development can transform not only their own capabilities but also those of their companies. The authors draw on 25 years of consulting experience and collaboration with psychologist Susanne Cook-Greuter to present a typology of leadership based on the way managers personally make sense of the world around them. Rooke and Torbert classify leaders into seven distinct actionlogic categories: Opportunists, Diplomats, Experts, Achievers, Individualists, Strategists, and Alchemists-the first three associated with below-average performance, the latter four with medium to high performance. These leadership styles are not fixed, the authors say, and executives who are willing to work at developing themselves and becoming more self-aware can almost certainly move toward one of the more effective action logics. A Diplomat, for instance, can succeed through hard work and self-reflection at transforming himself into a Strategist. Few people may become Alchemists, but many will have the desire and potential to become Individualists and Strategists. Corporations that help their executives and leadership teams to examine their action logics can reap rich rewards.