Israel M. Kirzner (born 1930) is an Austrian-American economist born in London who studied under Ludwig von Mises at New York University, earning his Ph.D. in 1957 and a faculty chair there in 1968. In Market Theory and the Price System (1963) and later work, he developed a theory of entrepreneurship centered on “alertness” to price discrepancies, through which entrepreneurs drive markets toward equilibrium. He taught at NYU until his retirement in 2001, building, with Ludwig Lachmann, an influential graduate program in the Austrian School tradition.