This Handbook provides a comprehensive overview of how environmental, social and governance (ESG) factors are reshaping long-term investment strategies. Leading experts demonstrate how ESG principles can guide investment choices, influence risk and return, and connect to broader goals such as corporate social responsibility and impact investing. Evaluating theories, methodologies, performance and practice, the Handbook explains the ideas behind ESG investing and how applications relate to real portfolios. Chapters explore topics including the use of AI and machine learning for measuring ESG performance, the issues surrounding sustainability reporting in global value chains and cognitive biases in ESG investing. Authors highlight the growing need for consistent and transparent data, as differing rating systems and reporting standards make it difficult to compare companies. Ultimately, the Handbook emphasises that ESG investing is becoming an essential part of modern finance but must overcome data and measurement challenges to reach its full potential. Bridging theory and practice, the Handbook of ESG Investing is a valuable resource for scholars and students of economics, finance and the environment. Its focus on policy and regulatory implications will also benefit policymakers and practitioners in the finance sector.