In most intra-state conflicts, rebel groups are at a disadvantage relative to the governments they combat. It is no surprise, then, that many fail to achieve their goals. But in Rules for Rebels, Max Abrahms provides an intuitive explanation for variation in militant groups’ success, written in the guise of a ‘rulebook’ for militants. First, he notes, successful groups recognize the costs of using violence against civilians (Rule 1). Organizations that harm civilians alienate supporters and invite intense repression campaigns. Of course, groups that target civilians may be systematically different in ways that also impinge on their success. Abrahms provides quantitative evidence from hostage situations that helps allay such concerns. Refraining from violence against civilians, however, is not always simple. By necessity, many militant groups are hierarchically flat, so even powerful leaders struggle to rein in the more indiscriminately violent rank-and-file. Abrahms’ Rule 2 highlights the advantages to rebels of leader control over subordinates. In so doing, it upends the conventional wisdom about the benefits of decentralization, arguing that the additional flexibility and resilience may come at a high political cost. The language, and logic, of Rules 1–2 derive from standard theoretical and empirical techniques in political science; Rule 3, however, draws additional insights from psychology and marketing, focusing on how militant leaders, like businesses, use strategies like branding to deal with competition and bad publicity. In general, Abrahms provides persuasive quantitative and qualitative evidence on the relationship between tactical and organizational variables, on the one hand, and outcomes like objective achievement. Rules for Rebels provides a number of logical, well-supported answers to questions of interest to both scholars and practitioners.