The main goal of this book has been to describe in more detail the principles of microwave diagnostics of ocean environments. The author hopes that this book gave the reader great insight into the problem. Indeed, the material selected and reported in this book demonstrates the potential capabilities of passive microwave techniques for the detection of complex hydrodynamic processes and events. The methodology is based on the precise high-resolution mapping, selection, and digital evaluation of microwave radiometric signatures. However, to achieve this goal, we have to invoke an extended remote sensing technology, including sophisticated instrumentation and digital processing. In this context, this book briefly explains how to make the impossible possible and simultaneously, it reveals numerous scientific advances in passive microwave remote sensing of the ocean.