This paper argues for broadening the application of hysteresis to institutions, policy lock-in, psychology, identity, and economic ideas. Hysteresis is an element of historical processes, and the real world is historical. That explains why hysteresis is pervasive and important. Hysteresis should be a fundamental building block of political economy. Expanding its application in economics is both an opportunity and a challenge. The opportunity is that it provides a means for incorporating political, sociological, and psychological forces which economics tends to neglect. That will enrich economics and can also provide a mutually enriching bridge to other social sciences. The challenge is introducing such concerns raises questions about the character of economics’ knowledge claims, which is likely to trigger resistance from economists.