Computer and network systems have given us unlimited opportunities of reducing cost, improving efficiency, and increasing revenues, as demonstrated by an increasing number of computer and network applications. Yet, our dependence on computer and network systems has also exposed us to new risks, which threaten the security of, and present new challenges for protecting our assets and information on computer and network systems. The reliability of computer and network systems ultimately depends on security and quality of service (QoS) performance.  This book presents quantitative modeling and analysis techniques to address these numerous challenges in cyber attack prevention and detection for security and QoS, including:  the latest research on computer and network behavior under attack and normal use conditions; new design principles and algorithms, which can be used by engineers and practitioners to build secure computer and network systems, enhance security practice and move to providing QoS assurance on the Internet; mathematical and statistical methods for achieving the accuracy and timeliness of cyber attack detection with the lowest computational overhead;guidance on managing admission control, scheduling, reservation and service of computer and network jobs to assure the service stability and end-to-end delay of those jobs even under Denial of Service attacks or abrupt demands. Secure Computer and Network Systems: Modeling, Analysis and Design is an up-to-date resource for practising engineers and researchers involved in security, reliability and quality management of computer and network systems. It is also a must-read for postgraduate students developing advanced technologies for improving computer network dependability.