The Introduction sets out the theoretical and empirical concerns of the book. Institutionalization is defined as a decision-making rule that allows power to pass from one leader to another. Institutionalization is, by definition, a set of rules that constrain the personalization of power. Leninism, as a mobilizing system, provides no such rule, and the repeated consolidation of power and the accompanying tendency to build personal networks prevent the system from institutionalizing. It should be noted that the elaboration of intra-party rules does not mean that such rules extend to the core leadership; rather they are rules that bind others. Finally, Leninism as a specific form of organization is different from the broader term “authoritarianism.” Inherent in the concept is the notion that Leninism develops through phases. Leninism under reform is subject to certain pathologies that weaken it.