This chapter discusses the tenets and propositions of some of the major theories and models that have shaped fathering research thus far. The theories and models provide a basis for defining and articulating different dimensions of what fathers do in families and the influence of their investment in and involvement on childhood development. Built on the groundbreaking work of J. Bowlby and M. D. Ainsworth, attachment theory has wide application for interpreting father–child relationships across cultures. At the heart of attachment theory is the development of close emotional ties to particular individuals. An influential conceptual framework that laid the groundwork for a number of the early studies on father involvement with children consisted of three core components: engagement, accessibility, and responsibility. Developmental psychopathology is a fruitful framework for understanding adaptive and maladaptive patterns of individual functioning in fathers and their links to childhood development at specific periods across the life cycle.