Book excerpt: Integrated Sensing and Communications for Future Wireless Networks: Principles, Advances and Key Enabling Technologies presents the principles, methods, and algorithms of ISAC, an overview of the essential enabling technologies, as well as the latest research and future directions. Suitable for academic researchers and post graduate students as well as industry R&D engineers, this book is the definitive reference in this interdisciplinary field that is being seen as a technology to enable emerging applications such as vehicular networks, environmental monitoring, remote sensing, IoT, smart cities. Importantly, ISAC has been identified as an enabling technology for B5G/6G, and the next-generation Wi-Fi system. ISAC brings together a range of technologies: radar sensing, reconfigurable intelligent surfaces, holographic surfaces through to high frequency terahertz, PHY security, channel signaling, multiple access, and machine learning. - Gives an overview of ISAC technology – its potential, the challenges and future research trajectory - Presents the future directions of ISAC - Includes discussion of the following technologies: i. Intelligent Metasurfaces for ISAC; ii. Machine Learning and AI for ISAC; iii. ISAC Waveform Design and Full-Duplex; iv. Millimeter Wave, Terahertz, and Beamforming for ISAC; v. Network Architectural Aspects of Integrating Sensing