This chapter is an introduction to the Handbook of Computing Education Research. It argues that computing education is an important field, due to the growing impact of computing in society and the workforce, and a timely field, as computing topics make their way into school curricula around the world. It discusses the organisation of the book, introducing the sections (and the themes running through the sections). The Foundations section serves a "textbook" function, intended to set our field in context, and to be a practical guide for new researchers. The Topics section contains chapters which explore the “state of the art”, illustrating the kind of problems that researchers trying to address, and why they matter. The chapter concludes with a discussion of the open and collaborative process by which the Handbook was written. The editors hope that the Handbook will serve as a useful resource for some time to come, as instruction for the novice, a guide for the curious, and a companion for the experienced.