Proceeding from the ethic that occupational therapy is the rightful keeper of its own practice and knowledge, this article strives to bring the profession's knowledge concerning the role of occupation in adaptation into sharp relief. Knowledge generated by many occupational therapists represented in the profession's historic literature, scholarship, practice models, position papers, and research is analyzed through a heuristic framework that distinguishes the process from the state of adaptation. This analysis offers evidence that, in the service of persons with profound and often medically incurable disabilities, occupational therapy has begun to explicate the role of occupation as a vital adaptive medium and cornerstone of quality in daily living. Related areas of knowledge development in which legitimate progress can be claimed are suggested. Nevertheless, it is argued that occupational therapy's knowledge must be further developed and its societal value better communicated through the concerted efforts of all practitioners, educators, and researchers.