The Cyber Defense Matrix is a comprehensive guide to cyber defense strategy and implementation, written by Sounil Yu, a seasoned cybersecurity professional. The book is divided into two main parts, the first of which focuses on the Cyber Defense Matrix itself, a four-quadrant framework that Yu developed to help organizations better understand their cyber defense needs and allocate resources accordingly. The four quadrants of the matrix correspond to the areas of prevention, detection, containment, and response, and the book provides detailed guidance on how to develop and implement effective strategies in each of these areas. The second part of the book delves into specific tactics and techniques that organizations can use to enhance their cyber defense capabilities, such as network segmentation, deception technologies, and incident response planning. Throughout the book, Yu emphasizes the importance of a holistic approach to cyber defense that encompasses both technical and organizational measures, and that is grounded in a deep understanding of the threat landscape and the risks faced by the organization. Overall, The Cyber Defense Matrix is an essential resource for anyone involved in cybersecurity strategy and operations, providing a wealth of practical guidance and insights that can help organizations stay ahead of the constantly evolving threat landscape.