Family firms represent over 90 percent of businesses around the world and often play a more significant role in the economies of nations. The impact of the family on organizational behavior and firm performance is the factor that makes the difference between family and non-family firms. To illustrate how the family as a variable can be used to generate theory in a broad explanatory sense, we need to investigate both micro- and macro-levels of organizations. At a micro-level, family firms’ heterogeneity may be explained in terms of how the family behaves and intervenes in the business. At a macro-level, a possible explanation of such diversity is the institutional context, that is the general framework that influences firms’ behavior and strategy along the dimensions of culture, innovation propensity, law, governance rules, economic and financial constraints, and so on. Indeed, the family as a social unit can be considered another dimension of the institutional context. The book contributes in all these directions through theoretical and empirical chapters from different institutional contexts.