Leading experts on Kalecki have contributed special essays on what economists in the 21st century have to learn from the theories of Kalecki. Authors include surviving students of Kalecki, such as Amit Bhaduri, Mario Nuti, Kazimierz Laski Jerzy Osiatynski, and Post-Keynesian economists such as Geoff Harcourt, Marc Lavoie, and Malcolm Sawyer.