This book demonstrates the potential of urine as a biomarker resource for early disease detection, covering the related theory, strategies, tools and findings. Biomarker is measurable changes associated with the disease. Blood, as a critical part of the internal environment, is closely monitored and controlled by the body to maintain homeostasis, especially in the early stages of diseases. In contrast, urine, as a form of waste excreted by the body, accumulates early and small changes of the body without homeostatic control. Accordingly, urine can offer an ideal resource for early biomarker discovery. The book discusses exciting preliminary applications of urine biomarkers for diseases affecting major biological systems. It is useful for scientists, clinicians, venture capitalists of related field. In the 2nd edition, most of the chapters are updated and reorganized according to the latest research. Many new chapters have been added to supplement the discussion of this area.