“Activist Economics” is a short, critical introduction to neoclassical (or marginalist) economics and to the basic principles of an alternative “political economy.” Both of these approaches to studying economies make important contributions to our understanding. But their perspectives are different. Neoclassical economists treat economic relations and outcomes as part of a technical system considered to be separate from human society, governed by its own universal or natural laws, and best studied from the standpoint of engineers and experts. In contrast, political economists treat economies as cultural systems indistinguishable from the wider society in which they are embedded, subject to political or social control, and best studied from the standpoint of the people enmeshed in and affected by them. Each session of “Activist Economics” critically examines a critical theme or assumption of mainstream economics, together with a cogent political-economic alternative. Each also includes active discovery exercises, short tutorials about key concepts and themes, and suggestions for further reading and study.