This book deals with the design, numerical simulation, state of the art fabrication processes and methods, qualitative and quantitative tests, and measurement techniques of wearable and flexible antennas of different topologies, such as: Planar Inverted F, Printed Monopoles, Micropoles and Microstrips. Novel trends, materials, and fabrication and measurement techniques used in this vital field of antenna systems are also discussed. To the best of the editor's knowledge, at the time of publication, there are no published books targeting the vital topic of flexible antennas specifically and/or serving as a complete reference. There are only few books on wearable antennas that deal with specific applications and this has initiated a motivation to propose a book that would serve as a complete technical reference of the addressed technology. This book can serve as a reference source for Research and Development scientists, RF and antenna engineers working in this vital field; moreover, it could be used as a text book for Antenna Theory and Advanced Antennas courses which are mainly offered for graduate students.