In behavior analysis, continuity refers to the assumption of a similarity of behavioral principles or processes between nonhumans and humans, which is often considered to be a fundamental postulate of the field. The present paper outlines a more recent view of the continuity assumption as an epistemological tool or research strategy. Researchers employing this strategy attempt to replicate with humans already-identified behavioral principles from nonhuman research prior to their application to socially relevant issues in natural settings. This form of the continuity strategy has flourished, despite demonstrable differences between nonhuman and human behavior, firstly in the study of performance on schedules of reinforcement and more recently in the study of derived stimulus relations. The implications of research on derived stimulus relations for the differing theoretical accounts of the continuity strategy are discussed.