Outdoor wayfinding and navigation systems and services have become indispensable in people's mobility in unfamiliar environments. Advances in key technologies (e.g., positioning and mobile devices), has spurred interest in research and development of indoor wayfinding and navigation systems and services in recent years. This book provides both breadth and depth of knowledge in designing and building indoor wayfinding and navigation systems and services. It covers the types of sensors both feasible and practical for localization of users inside buildings.