The subject of the book is application of multi-antenna radiolocation to the environment of fast, ubiquitous wireless communication among portable devices. It is a systematic presentation of the author's research and development in the field, within the 802.11b standard, while explaining the general principles and exploring applications to other standards and situations. The purpose is to fill a gap in the current technical literature and present the issues involved in locating mobile wireless network agents, in a single volume, accessible to system designers and other practitioners in the wireless field.