Developing Sustainable Supply Chains to Drive Value : Business Expert Press : 9781606493717 : 160649371X : 30 Oct 2013 : As we enter the 21st Century, we find ourselves faced by two major developments. The first is emergence of the supply chain as a critical strategic and tactical weapon. As has been pointed out by many researchers, with the emergence of the supply chain, the unit of competition has shifted from the firm to the supply chain. However, with the advent of the supply chain, it is important to recognize that we have to view strategic objectives within a context that stresses not simply the internal operations of the firm but also the elements of the supply chain - elements that include the supplier base, customers, logistics linkages, and relationships, both visible and virtual. We are now coming to realize that the supply chain is no stronger than its weakest link. The second development is that of sustainability. This is more than simply being environmentally responsible.