Real-time location awareness is essential for current and future wireless applications, particularly for 5G, Wi-Fi, and sensor networks. Reliable localization and navigation is a critical component for a diverse set of applications including smart cities, logistics, security tracking, medical services, search and rescue operations, automotive safety, and military systems. The coming years will see the emergence of location awareness in challenging environments with sub-meter accuracy and minimal infrastructure requirements. This special issue will cover the foundations and trends of localization and navigation technologies. In particular, foundations and algorithms will be covered in the first part, while experimentation and applications will be covered in the second part.