Commander Rick examines the impact of over-population, and the Zero Population Growth movement, on current ecological concerns. Featured guests include science fiction writers David Brin discussing his near future novel, Earth; Frederik Pohl, co-author (with Isaac Asimov) of the non-fiction ecology book, Our Angry Earth; Kim Stanley Robinson (Pacific Edge); Joe Haldeman (The Forever War); Jerry Pournelle (co-author, The Mote In God's Eye); Barry B. Longyear (Sea of Glass); and comic creator Paul Chadwick (writer/artist, Concrete).