Power transition theory and Graham Allison’s Thucydides Trap Project are discussed in tandem with two complementary aims: to highlight theoretical and empirical contributions of the power transition research program, and to provide critical perspective on the Thucydides Trap Project. Conventional-wisdom approaches of this sort are distinguished from power transition theory, the empirical international relations theory proposed by A. F. K. Organski and further articulated and tested by generations of scholars. The theory’s central elements—national power, stages of power transition, shifts in the distribution of power, international order and the status quo—are identified and discussed, with a focus on key variables used to explain war and peace among contending states. A comparative, critical examination of the Thucydides Trap Project is used as a lens for spotlighting key empirical contributions of the power transition theory research tradition and the value of adhering to norms of scientific rigor. Opportunities for further growth and development are noted, with special attention afforded to essential features of the power transition theory research program, including the study of (1) the timing and initiation of war; (2) rising powers’ dissatisfaction with the status quo, and a possible distinction between dissatisfaction and revisionism; and (3) reducing the risk of violent, revisionist challenges.