Research participants who have cognitive disability and difference may be considered a vulnerable population. At the same time, they should also be empowered to participate in research in order to foster the growth of knowledge and the improvement of practices that concern them. Participating in such research follows the Disability Rights Movement's call - "nothing about us without us." This volume provides timely, multidisciplinary insights into the ethical aspects of research that includes participants with cognitive disability and difference. These include conditions such as intellectual disability, autism, mild cognitive impairment (MCI), and psychiatric diagnoses. The chapters in this volume describe situations where difficulties arise, And explore strategies for empowerment and inclusion. They draw on both empirical and normative research to offer suggestions for research design, research ethics, and best practices that empower people with cognitive disabilities and differences to participate in research while respecting and managing potential coercion or undue influence. This interdisciplinary volume includes contributions from scholars in anthropology, sociology, ethics, child studies, health and rehabilitation sciences, philosophy, and law who address these issues in both clinical and social/behavioral research. It will be valuable for anyone conducting research involving these populations in the clinical, humanistic, or social sciences.