This book is intended to provide non-specialists an overview of the state of the art in microwave and high frequency hardware, measurement, and modelling as well as to give the specialists insight into the most advanced R&D topics of microwave and high frequency different disciplines. It deals not only with the application of radiation of 300 MHz to 300 GHz frequency to synthesis, heating or ionisation of matter but also with generation, transmission, and detection of microwave and radio frequency radiation. The topics were selected from contributions of the 8th International Conference on Microwave and High Frequency Heating, organised by AMPERE and held in September 2001 in Bayreuth, Germany. The papers were referred by major specialists in the respective field.