This chapter describes the relevance of critical thinking and the related process and philosophy of evidence-based practice (EBP) to cognitive behavior therapy and suggests choices that lie ahead in integrating these areas. Critical thinking in the helping professions involves the careful appraisal of beliefs and actions to arrive at well-reasoned ones that maximize the likelihood of helping clients and avoiding harm. Critical-thinking values, skills and knowledge, and evidence-based practice are suggested as guides to making ethical, professional decisions. Sources such as the Cochrane and Campbell Collaborations and other avenues for diffusion, together with helping practitioners and clients to acquire critical appraisal skills, will make it increasingly difficult to mislead people about “what we know”. Values, skills, and knowledge related to both critical thinking and EBP such as valuing honest brokering of knowledge, ignorance and uncertainty is and will be reflected in literature describing cognitive behavior methods to different degrees.