An application-oriented approach to the topic of sustainability in facility management requires practical reference values and key figures. The authors develop a definition of sustainability that connects it with the complex areas and processes of facility management. Significant insights and results for this book emerged from recent research, in which practical key figures for facility management were developed in collaboration with companies. An IT-supported system is presented that illustrates the flexible recording, management, measurement, and evaluation of sustainability metrics within the company. The system is described in its core functions.