This monograph shows that modern Industry 4.0. cyber systems do not have the required cyber resilience for targeted performance under heterogeneous mass intruder cyber-attacks. The main reasons include a high cyber system structural and functional complexity, a potential danger of existing vulnerabilities and "sleep" hardware and software tabs, as well as an inadequate efficiency of modern models, methods, and tools to ensure cyber security, reliability, response and recovery. A new formulation of the cyber resilience problem under heterogeneous mass cyber-attacks is proposed, in which the cyber system performance recovery in destructive software impacts prevents significant or catastrophic consequences.