Lobbying regulation is a transparency policy that sheds light on which lobbyists seek to influence public actors during policy development. Over 65 years of scholarship on it has seen the evolution of what can be broadly conceptualized as two generations of research. This paper conceptualizes the different themes in these two generations, where the developed classification system serves as a basis to understand common trends and differences to better situate the state of the art in the lobbying regulation literature today. After examining and explaining both generations in the first two sections of the paper, this is used as a basis to introduce the papers of this Special Issue/Collection in the third.