This chapter clarifies the public role which Jevons assigned to political economists. Jevons wanted to transform the study and status of political economy. I argue that, for Jevons, bolstering the scientific status of political economy was crucial because scientific knowledge was the basis of the political economist’s public role. Jevons believed that political economists had an educational role to play in society. They had to instruct people on correct economic behaviour, for the sake of society as well as for themselves. Scientific expertise gave economists the authority to act as guides for society. I thus argue that Jevons represents a step in the process of professionalisation and specialisation which took place in the final decades of the nineteenth century. I will explain how Jevons believed that political economy could become a true science by adopting a mathematical approach and complementing economic theory with inductive statistical data. I will then outline the main steps in the process of professionalisation, which was rooted in the development of the university system. I then argue that, through his economic theory, Jevons provided economic agents with prescriptions for correct behaviour, instructing them, for instance, on how to make rational consumption choices.