Environmental policies based upon comprehensive analysis of air, water, and land pollution (such as economic sector and community-based approaches) are becoming an important supplement to traditional single-medium approaches to environmental protection. Environmental regulatory agencies are beginning to embrace comprehensive, multi-statute solutions to issues related to permitting of facilities, compliance assurance, education and outreach, research, and regulatory development. The primary concepts that inspire the new policy direction are that releases of pollutants to any environmental medium (air, water, and land) affect other environmental media and that environmental strategies must identify and address those interrelationships actively through policies of the whole facility. One way to achieve a focus on the whole facility is to design environmental policies for similar industrial facilities. Under such an effort, environmental concerns that are common to the manufacture of similar products can be addressed in a comprehensive manner. The desire in the EPA Office of Compliance to move forward with this sector-based approach led to the creation of the sector notebooks.