This book explores the emerging paradigm of self-healing networks-digital infrastructures that can automatically detect, diagnose, and repair faults without human intervention. With growing reliance on uninterrupted connectivity across sectors like healthcare, smart cities, military, and autonomous systems, network resilience has become critical. The book explains key concepts such as fault tolerance, robustness, survivability, and adaptability, and shows how these are achieved through technologies like AI/ML, SDN, NFV, edge computing, blockchain, and digital twins. It outlines practical design principles for building networks that remain operational even in failure conditions, offering both theoretical foundations and real-world case studies. Written in an engaging, accessible style, the book serves as a guide for engineers, researchers, and decision-makers aiming to build intelligent, fault-tolerant, and highly available network systems.