This book introduces Participatory Design to researchers and students in Human-Computer Interaction (HCI). Grounded in four strong commitments, the book discusses why and how Participatory Design is important today. The book aims to provide readers with a practical resource, introducing them to the central practices of Participatory Design research as well as to key references. This is done from the perspective of Scandinavian Participatory Design. The book is meant for students, researchers, and practitioners who are interested in Participatory Design for research studies, assignments in HCI classes, or as part of an industry project. It is structured around 11 questions arranged in 3 main parts that provide the knowledge needed to get started with practicing Participatory Design. Each chapter responds to a question about defining, conducting, or the results of carrying out Participatory Design. The authors share their extensive experience of Participatory Design processes and thinking by combining historical accounts, cases, how-to process descriptions, and reading lists to guide further readings so as to grasp the many nuances of Participatory Design as it is practiced across sectors, countries, and industries.