Think of a company as a person trying to lose weight. The usual financial accounts are like a bathroom scale — they show the total number, but not whether you ate too many sweets or not enough vegetables. Sustainability management accounting is the food diary that tracks every ingredient, so you can make smarter choices and feel healthier in the long run. In this chapter, we explore how managers can weave environmental and social concerns right into their everyday numbers, turning good intentions into better decisions.