In bladder cancer, variations in clinical course and treatment outcomes support the concept that the condition may comprise a compendium of different types of tumor diathesis with unique, albeit interrelated, pathways of development. This concept and the schema of developmental pathways of bladder cancer derived from it are intended to complement the traditional classification used to stage bladder cancer, providing a perspective on the potential evolution of a particular malignancy over time. The schema represents the intrinsic biologic potential of various types of bladder cancer. It also indicates a given tumor’s likely behavior as can be predicted by its histopathologic appearance at a given point in time, what may be expected through specific interventions, how approaches to treatment may need to be adjusted in considering the pathway a specific tumor may follow, as well as how the disease course may reflect genetic changes associated with the generation of a specific malignant diathesis. These considerations and the concept of specific but interrelated pathways of development in bladder cancer are presented in their historical context and current clinical use.