This Handbook presents the state-of-the-art of Life Cycle Sustainability Assessment (LCSA) practice and provides guidance for its implementation and outlook for future work. Spotlighting sustainability analysts, managers and overall decision-makers from private and public sectors as well as experts in academia, it covers the historical background and current global context for life cycle sustainability assessment, methods and data management advancements. Highlighting best practices on how LCSA is used for each of the sustainability pillars (environmental, economic, and social) from a life cycle perspective, the Handbook illustrates how results can then be integrated into the decision-making process. Its use of sectoral and policy cases also illustrates the feasibility of using these results when putting in place life cycle sustainability management. Chapters further investigate developments like responsible sourcing and the transition to a circular economy requiring consideration for expanding the uptake of LCSA by global markets, and low- and middle-income countries. The Handbook on Life Cycle Sustainability Assessment will be an excellent resource for academics and researchers who are interested in both social sciences and natural sciences and engineering. It will also be of great interest to business, professionals and policy makers who are interested in not only the environment but also in important social and economic considerations as we move towards a low carbon and more sustainable future economy.