The book defines a knowledge graph as a structured representation of information, typically in the form of triples (subject, predicate, object), that can be used to model real-world entities and their relationships. It explores the role of knowledge graphs in the digital economy by highlighting their ability to empower various applications and processes. The book discusses how knowledge graphs facilitate data integration, enhance decision-making, and enable personalized services. It also covers the development of knowledge graph technologies, including knowledge representation, reasoning, and semantic computing, and their applications in areas like natural language processing, information retrieval, and recommendation systems. The book emphasizes the importance of knowledge graphs in driving innovation and growth in the digital economy.