We investigate the concept of economic power in the three main paradigms of economic thinking in the 20th century: neoclassical, marxist and institutionalist. We propose a reconstruction, based on a new taxonomy, of the various forms of power conceptualized by each of them. In particular, we claim that the neoclassical paradigm contains a consistent although often implicit theory of power. We then show that many controversies between these paradigms were debates on power and that some shifts in mainstream economics in the 1970s and 1980s are a reaction to the criticisms leveled against the neoclassical conceptualization of power.