Cybercriminals and nation-state groups are now developing customized malware and cyber weapons to target critical infrastructure, which enables cyber warfare and espionage on a large scale. Legacy security strategies are not adequate in dealing with new threats. The book recommends newer offensive-minded defenses focusing on extensive logging, traffic analysis, penetration testing, and incident response preparations. This book also offers specific hardening recommendations, including access controls, multifactor authentication, micro-segmentation, deception tools, and encryption. Artificial intelligence is a game-changer for defenders against automated, high-volume threats. Machine learning techniques, such as user behavior analytics, deep learning, reinforcement learning, and generative adversarial networks, are ethical tools that can augment human capabilities around threat detection, investigation, and orchestrated response. However, risks are associated with AI-powered hacking tools and adversarial attacks that exploit model weaknesses. This book explores hacker traits like curiosity, persistence, and creativity required to reveal subtle flaws. It details common techniques in reconnaissance, vulnerability probing, malware delivery, credential theft, and lateral movement traversal. Readers gain frameworks for emulating hacker thinking, analyzing attack vectors, and testing defenses via red teaming for robust security hardening. This book provides a comprehensive overview of modern cybersecurity risks and developments, such as hacking-as-a-service, which enable threats. It also covers legacy control gaps and emerging AI-amplified practices that could give defenders the advantage to combat highly capable adversaries across digital ecosystems.