For a long time, when people thought about the environment they thought mostly about things they wanted to conserve: forests, species, oceans. But now we know that environmentalism is also about things we produce: houses, offices, factories. The Innovators we bring you here are all involved with what has come to be known as "green building." They include a Massachusetts "solar zealot" making sun power more affordable for homeowners, a couple in India developing eco-friendly communities, an Italian promoting concrete that "eats" air pollution and a Texas crusader for greener hospitals. They all want a world where concern for the earth is "built in" from the start.