This open access book offers an introduction to the field of knowledge-based product configuration. It is designed for industry practitioners interested in the practical aspects of product configuration, as well as students seeking to learn about or conduct research in this domain. To this end, the book is organized into nine chapters. After a general introduction (chapter 1) which also sets the terminology and outlines the benefits, the authors delve into the details of the scope of product configuration (chapter 2) and the business context, including architectures and interfaces to other systems (chapter 3). Next are a separate chapter on modelling that introduces three layers of representation in product configuration (chapter 4) and one providing an overview of configuration technologies (chapter 5). Towards the end of the book, chapters address the main challenges in practice: quality (chapter 6) and performance tuning (chapter 7). Finally, two chapters provide insights on important current research directions: chapter 8 describes how generative AI such as large language models (LLMs), chatbots, foundation models and similar technologies could be utilized as user interfaces for configurators or to support configuration processes; and chapter 9 addresses the incorporation of sustainability and lifecycle information in product configurators. All chapters contain examples and exercises to support the reader&s learning journey. The purpose of these exercises is to deepen the reader&s understanding of the chapter, for example by applying the covered topics in practice. The authors bring extensive experience to this book, having worked for many years with Siemens& research. Their work encompasses developing product configurators for various Siemens business units, supporting product managers in tool selection, conducting research on configuration technologies, and teaching configuration-related courses for students at the University of Klagenfurt and at the Graz University of Technology in Austria.