This introductory chapter sets the stage for the book by outlining its motivations and objectives in exploring the topics of reskilling and upskilling. It provides an entry point into the topic by emphasizing the growing importance of reskilling and upskilling measures in shaping the present and future world of work. The chapter clarifies key terminology and conceptual foundations, offering an overview of the historical evolution of reskilling and upskilling, with more in-depth discussions presented in subsequent chapters. It also examines how these approaches to organizational learning have evolved over time within the broader work landscape, addressing the question of whether they represent new developments or long-standing practices. Finally, this chapter introduces the book’s overall structure and highlights the thematic focus of each chapter.