This book systematically presents the wireless sensing technology, which has become a promising sensing paradigm in recent years. It includes the introduction of underlying sensing principles, wireless signals, sensing methodologies and enabled applications. Meanwhile, it provides case studies to demonstrate how wireless sensing is applied for representative human and object sensing applications. This book also provides a wireless sensing framework as a guidance to understand and design a wireless sensing system or prototype based on their needs. It also presents a critical investigation of the challenges in achieving wireless sensing in both signal-level and application-level contexts. Accordingly, it summarizes the typical solutions to tackle the related challenges. Researchers and advanced-level students in computer science or electrical engineering working on the design of a wireless system will find this book useful as a reference. Professionals working in the wireless sensing industry will also find this book valuable as a reference tool.