 Despite its prominence in the contemporary life sciences, molecular biology is a relatively young discipline, originating in the 1930s and 1940s, and becoming institutionalized in the 1950s and 1960s. It should not be surprising, then, that many of the philosophical issues in molecular biology are closely intertwined with this recent history. This section sketches four facets of molecular biology’s development: its origins, its classical period, its subsequent migration into other biological domains, and its more recent turn to genomics and post-genomics. The rich historiography of molecular biology can only be briefly utilized in this shortened history (see, for example, Abir-Am 1985, 1987, 1994, 2006; Burian 1993a; Canguillhem 1989; de Chadarevian 2002, 2003; de Chadarevian and Gaudilliere 1996; de Chadarevian and Strasser 2002; Deichmann 2002; Fisher 2010; Hausmann 2002; Holmes 2001; Judson 1980, 1996; Kay 1993; Marcum 2002; Morange 1997a, 1998; Olby 1979, 1990, 1994, 2003; Powell et al. 2007; Rheinberger 1997; Sapp 1992; Sarkar 1996a; Stegenga 2011; van Holde and Zlatanova 2018; Witkowski 2005; Zallen 1996. Also see autobiographical accounts by biologists, such as Brenner 2001; Cohen 1984; Crick 1988; Echols 2001; Jacob 1988; Kornberg 1989; Luria 1984; Watson 1968, 2002, 2007; Wilkins 2003).