This document discusses comparative adult education. It defines comparative adult education as an approach to understand adult education by reflecting on the similarities and differences between education systems in different countries. The history of comparative adult education developed in 19th century France and blossomed in Europe and the USA in the 20th century. The document presents two main findings: first, that comparative adult education is an everyday experience, and second, that comparative adult education research is evidence-based. It concludes by revisiting some key aspects of comparison.