He is author of The Green Crusade: Rethinking the Roots of Environmentalism (Rowman and Littlefield), and editor of Conservation Reconsidered: Nature, Virtue and American Liberal Democracy (Rowman and Littlefield). In addition to his work on environmentalism, his studies focus on topics at the intersection of political philosophy and public policy such as sprawl and city planning theory, the problem of earth/asteroid collisions, and the scientific search for extraterrestrial intelligence