A theory of mental self-government is presented that proposes a set of intellectual styles as a bridge between intelligence and personality. According to the theory, intellectual styles can be understood as governmental in (a) function (legislative, executive, judicial), (b) form (monarchic, hierarchic, oligarchic, anarchic), (c) level (global, local), (d) scope (internal, external) and (e) leaning (conservative, progressive). The article is divided into four main parts. The first discusses alternative models for understanding intelligence, including geographic, computational, and anthropological ones. The second part presents the model of intelligence as mental self-government, and presents a theory of intellectual styles based upon this model. The third part discusses the development of intellectual styles. The fourth part summarizes main points, and discusses the main conclusions to be drawn from the article. A key point to understanding performance in school, work, and personal life is that people naturally seek to match their preferred intellectual styles to tasks and situations that draw upon these styles. As a result, it is necessary in counseling, diagnosis, and training, to take into account styles as well as level of intellect.