This class elaborates some of the theoretical foundations for the ongoing research of the Urban Theory Lab on the contemporary “urban revolution”. Such an investigation requires considerable conceptual and methodological innovation, not least because inherited approaches to urban theory and research generally take for granted the very distinction between city and non-city spaces that is today being radically superseded. We here explore the problematique of planetary urbanization in four steps. First, we survey the legacies of city-centric epistemologies and cartographies in several key approaches to urban theory. Second, we critically evaluate several key strands of late 20th and early 21st century urban theory with particular attention to their treatment of the “global” dimensions of urbanization (Marxist urban theory and global city theory). Third, through a close reading of key works by Henri Lefebvre, David Harvey and more recent contributions, we elaborate some conceptual foundations for approaching newly emergent, planetary patterns of urbanization. Fourth, we consider some of the major debates in contemporary urban theory, in relation to which the conceptualization of planetary urbanization has been articulated.