The monograph is devoted to the study of the integration of three major areas of modern data analysis: Big Data, OSINT (Open Source Intelligence), and AI (Artificial Intelligence), with particular emphasis on methods for constructing and applying semantic networks and the use of Large Language Models (LLMs). The material is organized according to a principle of gradual progression from fundamental concepts and technologies for working with Big Data to methods of open-source intelligence, intelligent information analysis, artificial intelligence applications, graph-based knowledge models, and decision support systems. This structure provides a comprehensive understanding of modern information and analytical technologies, makes it possible to trace the relationships between individual methods and tools, and establishes a solid methodological foundation for their practical application in OSINT.The monograph is intended for researchers, OSINT analysts, cybersecurity specialists, developers of intelligent systems, as well as academic and teaching staff and students in the fields of data analysis, information security, and applied artificial intelligence.