This book is for people who want to understand what mobile location services are and what type of mobile location service applications are being built today. This book is also for those who want to grasp the underlying mobile location service platform technology for evaluation purposes and who want to understand the technical architecture that must be employed to support a carrier-class mobile location service application. For the technically oriented, the book focuses on the many technical challenges that mobile location service applications face. Although some technology industry background is assumed, this book is not a programming manual and is accessible to readers with even the most basic programming and systems engineering background.