This book offeres us a comprehensive introduction of UWB-aided positioning techniques including measurement, positioning, tracking, error analysis, performance bounds, ranging protocols, practical applications, up-to-date developments and future research directions. In terms of content, this book is highly recommended to electrical engineers who either need a high-level picture or in-depth understanding of the technical details. Since this book fully focuses on the positioning problem, it is able to include many discussions that have been occasionally overlooked, such as the Ziv-Zakai bound. As a preliminary knowledge of the main theme, chapter 2 and chapter 3 can also be used for general purposes to understand the basic of UWB. In addition, each chapter ends with problems, some of which are quite inspiring. Graduate students are strongly encouraged to choose their interesting problems to work on. The last chapter gives a concise survey of the recent developments and future research directions. Reading this chapter may help people, especially graduate students form their own ideas.