"The purpose of this book is to further communication and understanding of the status and future of radio science, both for those working in the field, and for those who want to know what is of current importance in this area. The International Union of Radio Science, URSI (Union Radio-Scientifique Internationale), has divided the subject of ""Radio Science"" according to the ten topics of the Commissions that make up URSI: * Electromagnetic metrology * Fields and waves * Signals and systems * Electronics and photonics * Radio astronomy * Electromagnetic noise and interference * Wave propagation and remote sensing * Ionospheric radio and propagation * Waves in plasmas * Electromagnetics in biology and medicine This book consists of 37 original, peer-reviewed papers. The topics, authors, and reviewers were selected by the URSI Commissions. Each paper provides a critical, in-depth review of and, in many cases, tutorial on advances and research that have been of significant importance within the area of interest of the Commissions during the past three to four years. Among the 37 topics covered are the following: * Two-way satellite time and frequency transfer * Handset antennas for mobile communications * Wireless ATM networks * Ultra-high-bit-rate optical communication systems * Modeling techniques for EMC analysis * Mobile, terrestrial, and satellite propagation modeling * GPS and the ionosphere * Radio-frequency sounders in space * The early radio universe * Exposure assessment for handheld mobile communications devices A ""Collected References"" CD-ROM is an integral part of this book, intended to permit a reader to install the bibliographic database on a personal computer or workstation, so that it can be searched as needed. Independently of the papers in the book, the CD-ROM contains key references on the topics each Commission has deemed to be most significant during the triennium. The full titles are included in the references, and they are augmented by keywords including the country of origin for the work, to facilitate searching for the most important references on a particular topic.".