Contrast Agents for Optical Imaging.- Dynamic and Continuous Monitoring of Renal and Hepatic Functions with Exogenous Markers.- Ultrasound Contrast Agents: Development of the Field and Current Status.- Chemistry of X-Ray Contrast Agents.- Iodinated Contrast Media: from Non-Specific to Blood-Pool Agents.- Liver-Specific X-Ray Contrast Agents.- Chemistry of ? +-Emitting Compounds Based on Fluorine-18.- Fundamentals of Receptor-Based Diagnostic Metalloradiopharmaceuticals.