In this introduction, I present the aim of this book: to study Jevons as a social scientist. I argue that Jevons’s thought and work are emblematic of the concerns and scope of Victorian social scientists, who aimed to identify the laws of nature to improve society. Victorian social scientists believed that there was continuity between the natural and the social. Moreover, they saw social science as public engagement. I show how, in the second half of the nineteenth century, scientific knowledge entered a process of specialisation. The figure of the intellectual also changed: intellectuals became increasingly professionalised. The basis of the intellectual’s claim to authority in public life also changed. I show that Jevons embodied this change, while maintaining that social science implied public engagement. Scientific enquiry aimed to identify natural laws for the improvement of society. After presenting Jevons’s biography and main works, I discuss the secondary literature on Jevons. This book, an intellectual biography of Jevons, explores many different facets of his thought, contextualising it in his intellectual and historical background. The main contribution of this book is to show that Jevons’s scientific endeavours were driven by the aim of using knowledge to improve society.