Throughout the ages, people have sought ways to formalize computational procedures in order to make them available for non-experts, and ultimately to automate them using computing machinery. The long quest for computational thinking (CT) developed over centuries through increasingly sophisticated innovations in computational processes, techniques, models, machines, and systems. This chapter outlines some historical roots of modern CT. It distinguishes between beginner CT, which is primarily aimed at the basic rules of CT for teaching in K–-12 education, and advanced CT, which encompasses a rich body of ideas, skills, and practices of computing professionals at their work. The chapter explains the risks involved in interpreting CT as a new phenomenon devoid of its long history, and it presents a broad, balanced view of CT that emphasizes ideas unique to the whole of computing as a discipline and that portrays the field in all its richness.