This book offers the first comprehensive coverage of microwave medical imaging, with a special focus on the development of novel devices and methods for different applications in both the diagnosis and treatment of various diseases. Upon introducing the fundamentals of electromagnetic imaging, it guides the readers to their use in practice by providing extensive information on the corresponding measurement and testing techniques. In turn, it discusses current challenges in data processing and analysis, presenting effective, novel solutions, developed by different research groups. It also describes state-of-the-art medical devices, which were designed for specific applications, such as brain stroke monitoring, lymph node diagnosis, image-guided hyperthermia, and chemotherapy response monitoring. The chapters, which report on the results of the EU-funded project EMERALD (ElectroMagnetic imaging for a novel genERation of medicAL Devices) are written by leading European engineering groups in electromagnetic medical imaging, whose coordinated action is expected to accelerate the translation of this technology "from research bench to patient bedside". All in all, this book offers an authoritative guide to microwave imaging, with a special focus on medical imaging, for electrical and biomedical engineers, and applied physicists and mathematicians. It is also intended to inform medical doctors and imaging technicians on the state-of-the-art in non-invasive imaging technologies, at the purpose of inspiring and fostering the translation of research into clinical prototypes, by promoting a stronger collaboration between academic institutions, industrial partners, hospitals, and university medical centers.