The qualitative part of the exploratory sequential mixed-methods study uses process tracing to reconstruct the historical trajectories in three chosen smaller medium-sized municipalities pioneering digitalization. It addresses the first two research questions: namely, what characteristics does the governance of digital policy have and which factors influence it? This chapter introduces historical institutionalism as a research approach, operationalizes the dependent variable governance of digital policy, and discusses explanatory factors for the governance of digital policy in the literature. The methodological considerations underpinning the study are discussed, such as causal chains, within-case inference, and data collection in process tracing. The criteria for selecting the three municipal case studies are presented.