This handbook presents a bold rethinking of Human Systems Integration (HSI) within Sociotechnical Systems (STSs), capturing the shift from traditional human-machine interaction to a dynamic, multi-agent systems approach. Drawing from various disciplines, including human factors, ergonomics, systems engineering, and artificial intelligence, the handbook explores the integration of technology, organizations, and people in increasingly complex and digitalized environments. The evolution reflected in these pages aligns with broader societal trends, from the rise of digital engineering and virtual prototyping to the growing necessity for holistic, context-aware design in life-critical domains. Fully updated, this new edition provides the tools and perspectives to shape resilient, intelligent, and human-compatible systems. As a comprehensive and reorganized reference spanning 14 sections and 45 chapters authored by leading experts from diverse fields, the handbook explores models, methods, and real-world applications that support the design, development, and management of complex STSs. Key topics include human-autonomy teaming, performance support, scenario-based design, organizational maturity, and the crucial role of tangibility in digital systems. For professionals focused on AI integration, safety assurance, or enhancing user experience across system lifecycles, the resource offers actionable insights and proven frameworks to meet the challenges of modern system complexity. Readers gain a thorough, helicopter view of HSI and STSs in various usable contexts. Handbook of Sociotechnical Systems: A Human Systems Integration Approach , Second Edition is an essential resource for engineers, designers, researchers, policymakers, practitioners, and educators who work with people, technology, and organizations. The content proves especially valuable for those involved in high-stakes, high-complexity environments such as aerospace, defense, healthcare, energy, and public systems.