This paper explores long wave theory, including Kondratieff's theory of cycles in production and relative prices; Kuznets' theory of cycles arising from infrastructure investments; Schumpeter`s theory of cycles due to waves of technological innovation; Goodwin`s theory of cyclical growth based on employment and wage share dynamics; Keynes-Kaldor-Kalecki demand and investment oriented theories of cycles; and Minsky's financial instability hypothesis whereby capitalist economies show a genetic propensity to boom-bust cycles. This literature has been out of favor for many years but recent developments suggest a reexamination is warranted and timely.