This open access book is one of the most promising core technologies in future communication systems for a variety of new wireless application scenarios, such as unmanned aerial vehicles (UAVS), the Internet of Things (IoT), and smart factories. This is mainly due to its ability to integrate traditionally separate wireless communication and sensing functions, thereby significantly reducing hardware complexity and power consumption. The combination of full-duplex (FD) technology with ISAC technology (FD-ISAC) brings additional advantages over traditional Time Division Duplex (TDD)-based ISAC systems. Full-duplex technology enables simultaneous transmission and reception of signals, thereby minimizing communication delays and perceived blind spots. This capability allows FD-ISAC systems to achieve higher communication throughput and better perceptual performance in dynamic, demanding environments. This book provides a comprehensive and detailed introduction of FD-ISAC systems, focusing on their principles, techniques, and practical applications. This book firstly introduces the signal model, channel model and beamforming technology of ISAC, and the self-interference signal model of full-duplex system, respectively. And on this basis, the system model of FD-ISAC is constructed, which can realize the communication and sensing functions at the same time. The key signal processing technology flow of the FD-ISAC system, such as the self-interference cancelation processing, the identification of the interfering signal, the echo signal, etc., are described. This book also discusses the hardware requirements for realizing FD-ISAC systems. Advanced hardware implementation solutions are proposed, including communication modules based on full-duplex self-interference cancelation (SIC) technology and specialized FD-sensing modules. In addition, recent research advances in FD-ISAC SoC technology are reviewed, highlighting both domestic and international research progress. These advances are critical to the commercial viability of FD-ISAC systems, as SoC designs provide a compact and cost-effective solution for integrating the necessary communication and sensing functions on a single chip.