This chapter examines the development of strategic planning practices from around 1960. Strategic planning advanced on the prior practice of long-range planning by emphasizing choice, competition, and control. It also made an initial step towards more open forms of strategizing by widening the discourse of strategy among managerial elites. Strategic planning’s rise was supported by three exogenous forces: growing organizational complexity, a culture of rationality, and new analytical technologies. Nevertheless, strategic planning’s development still took two kinds of arduous and fallible institutional work: ‘rule-making’ and ‘resource-organizing’. Under the first, corporate strategists, such as Shell’s Pierre Wack, created and disseminated techniques, such as scenario analysis, while consultants, such as BCG and McKinsey, promoted portfolio analysis. Under the second, entrepreneurs, such as Bruce Henderson, had to create new consulting organizations, such as BCG, and corporate strategists, such as Jack McKitterick at General Electric, built the first corporate strategy units.