The authors address the question of whether multinational corporations can use their economic power for the good of the environment and to stimulate sustainable development. The possibility is discussed in the light of the failure of governments to agree clear and binding environmental commitments and the increasing polarization between North and South countries. While transnationals are currently presenting themselves as the "green alternatives" in a global honour of need, there is no doubt that historically they have been a major source of economic and environmental problems both on local and international scales. The question addressed here is: is the gigantic economic power of these corporations an obstacle or a bridge to sustainable development? The authors review the UNCED process, and the day to day running of the transnationals. They examine the consequences of these companies' investment policies, and their involvement in mining, agriculture, trade, distribution and service industries. The final chapter discusses the far-reaching effects on national environmental policies of the new GATT and WTO agreements, and what the likely outcome will be if international environmental management is placed in corporate hands.