This book provides a comprehensive overview of the latest theory and practice on Patient and Public Involvement (PPI) in research. Its seven chapters cover the historical and conceptual background; the various ways implementation can be approached and how they are put into practice; ethical considerations and critical perspectives, including on the potentially negative impacts of PPI; approaches to meaningful evaluation; a step by-step guide to planning PPI and conclusions with considerations for future research. Drawing on current literature, this book provides an essential reference work for research students and all who want to better understand PPI in practice. It offers exercises to address key questions, case