The field of protest and contentious action is massive. Numerous studies have focused on the determinants of such behavior, among which are grievances and deprivations, resources, political opportunities, and general contextual conditions. Others have examined the changes in political protest over time and across countries, or the consequences of contentious action. Moreover, research on protest politics is characterized by a multitude of methodological approaches, which are not easy to group according to the “qualitative–quantitative” divide. To navigate this literature, three units of analysis are examined: individuals; groups, organizations or social movements; and protest events. This perspective can guide researchers through the field, in particular through the main factors for protest studies cross-temporally and cross-nationally, about their effects, and through the various methodological approaches. This perspective also might suggest possible directions for future research to overcome some limitations of the current literature.