Undoubtedly, research and clinical practice are much more advanced in the general ageing population than in persons with intellectual and developmental disabilities, and so professionals and academics must be made fully aware of commonalities and idiosyncrasies of older people with intellectual and developmental disabilities. This book presents the ongoing developments concerning mental health and aging, which will become relevant to the intellectually disabled population. Through experience, this book also acknowledges that the impact on the persons themselves and on their carers always needs to be taken into account, with treatment programs established with a multi-faceted team approach in mind. Avoiding the jargon of many titles in this area while maintaining the hands-on approach of clinical practice, this book meshes the practical and scientific worlds, with all chapters written by leading experts in the field. Beyond the US, the IASSIDD support expands the book message worldwide.