The first edition of The Paris System for Reporting Urinary Cytology introduced a completely new paradigm for detecting bladder cancer by urine cytology. This system concentrated on defining morphological characteristics of the most clinically significant form of bladder cancer, High Grade Urothelial Carcinoma. This new approach has been widely accepted throughout the world, and has become part of the daily practice of cytology. Considering that the first edition of The Paris System (TPS) introduced a new model of urinary cytodiagnosis, verification and expansion of initial material and data were anticipated. Based on evolving knowledge and readership requests, the group of highly experienced authors have created a new edition of TPS. This second edition includes areas and issues not originally covered. A new chapter on urine cytology of the upper tract, a rarely addressed topic, has been introduced. Furthermore, the issue of cellular degeneration is discussed in the criteria of all diagnostic categories. Examples of standardized reports are included in each chapter. Most importantly, a separate chapter presents data defining the risk of malignancy (ROM) for each diagnostic category to inform clinical management. New high quality images augment those of the first edition to better illustrate diagnostic clues and potential pitfalls. In addition to chapters on diagnostic criteria, current concepts of pathogenesis of bladder cancer, specimen adequacy and preparation, and ancillary tests are covered in separate chapters. A bonus to the volume is a comprehensive history of urine as the earliest diagnostic sample of human disease, richly illustrated with artworks from major museums.