Once upon a time supply chains had lots of inventory and apparel manufacturers had the luxury of warehouses and distribution centres stocked with finished products, so when customer demand would come in, product would be pulled from that stock. At the highest levels, demand-driven manufacturing - along with lean manufacturing, the theory of constraints and more - are simply processes designed to get apparel companies to move toward a make-to-order model. Most companies make product then inventory it. When they get orders they replace them against the inventory already made. They make, then store, then sell from inventory they hold. This report looks at the key issues and challenges in this area, and also the available and developing technology.