Reflections on the Development of Relational Frame Theory 25 Years on from “The Purple Book”: A Lot Done, More to Do

Martin Finn et al.. (2026). Reflections on the Development of Relational Frame Theory 25 Years on from “The Purple Book”: A Lot Done, More to Do. Perspectives on Behavior Science. https://doi.org/10.1007/s40614-026-00529-w.