The Environmental Engineering Handbook provides a comprehensive, multidisciplinary foundation for understanding and addressing today’s most complex environmental challenges. Designed for graduate students, educators, and early-career practitioners, the book integrates science, engineering, governance, policy, and societal dimensions, offering a holistic framework for sustainable decision-making in an evolving global landscape. Part I — Environmental Governance, Ethics & Engineering Diplomacy introduces readers to the institutional and legal architectures that shape environmental action. It covers the fundamentals of engineering diplomacy, European environmental and climate law, the EU Green Deal, renewable energy regulations, and global environmental treaties. The section also details Environmental Impact Assessment (EIA) and Strategic Environmental Assessment (SEA), highlighting their processes, criteria, and role in participatory decision-making. Together, these chapters equip engineers with the legal and diplomatic literacy required to operate effectively in international and interdisciplinary contexts. Part II — Equity, Society & Sustainable Education emphasizes the human dimension of engineering practice. It explores how inclusion, social equity, and environmental justice intersect with technological development, and provides strategies for integrating diversity, transversal competencies, and fair assessment into higher education. By framing sustainability as both a technical and societal endeavor, this part encourages future engineers to design solutions that are accessible, just, and community-centered. Part III — Water, Waste & Environmental Systems Management offers a rigorous treatment of core environmental engineering fields. Topics include water resources management, hydrological modeling, advanced wastewater treatment, solid waste management, sludge valorization, and life-cycle assessment. The section provides both conceptual frameworks and practical tools essential for managing water and waste systems efficiently, safely, and circularly. Part IV — Energy Systems, Buildings & Natural Radioactivity bridges building physics and energy systems engineering with environmental sustainability. It covers energy-efficient design, European building directives, digitalization tools such as IoT and digital twins, and eco-design approaches. The part also provides an in-depth examination of indoor radon, including measurement, mapping, regulation, and mitigation strategies. Complementary chapters on risk assessment and fossil-versus-renewable energy transitions equip readers with analytical frameworks for evaluating hazards, energy systems, and land-use strategies. Part V — Atmospheric Environment & Air Quality Engineering presents scientific, technical, and policy perspectives on air quality. It spans atmospheric chemistry, emissions trends, remotesensing applications, health impacts, monitoring techniques, modelling tools, and region-specific case studies—including Uzbekistan’s atmospheric conditions. This section also engages in applied debate on energy transition strategies, enabling students to explore real-world environmental trade-offs. Part VI — Cross-Cutting Methods and Engineering Tools consolidates essential competencies for modern environmental engineers. It introduces data science (Python, R, GIS), machine learning applications, remote sensing platforms, sensor networks, life-cycle thinking, multicriteria analysis, and project management standards such as ISO 21500. These tools support robust analysis, monitoring, and evidence-based planning across environmental domains. Part VII — Case Studies and Applications demonstrates how interdisciplinary principles are translated into practice. It presents applied examples in urban sustainability, industrial ecology, climate adaptation, and innovative engineering solutions. Regional dossiers on the European Union and Central Asia provide contextualized insights into governance, environmental pressures, and sustainable development pathways. Overall, the Environmental Engineering Handbook equips learners with the technical depth, societal awareness, and methodological versatility required to lead the next generation of environmental solutions. By merging engineering rigor with ethical, social, and diplomatic considerations, it prepares professionals to operate effectively in a world where environmental challenges are increasingly interconnected and global in scale.