Comparison has become such a routine practice in urban research that some do not hesitate to speak of a “comparative turn” or even a “renaissance” of the comparative gesture in urban studies. Nevertheless, writings aimed at justifying, clarifying and theorizing comparison in urban studies, and providing it with solid epistemological and methodological foundations, are quite rare. The variabilistic precept imposes comparison as a method whose central purpose is to test variables – nominal or ordinal – in order to identify the variable or variables that cause the cases to diverge. Approaches that value data constructed from a limited number of cases are fairly common in the social sciences. In the comparative monographs approach, the construction of objects, categories and even variables is accomplished by going back and forth between the different cases. The current discussions around urban neoliberalism provide a good example of the virtues of comparative monographs.