Seager's field of study is the religions of the United States. His interests include immigration, ethnicity and religion, and religion and the environment, but he has written most extensively about Asian religions in this country. His first two books were devoted to the World's Parliament of Religion in Chicago in 1893. More recently, he published Buddhism in America (Columbia, 1999), an examination of prominent communities and leading figures in a range of Buddhist traditions currently setting down roots in this country. Seager published his latest book, Encountering the Dharma (University of California Press) in March, 2006. It offers a rare insider's look at Soka Gakkai Buddhism, one of Japan's most influential and controversial religious movements, and one that is experiencing explosive growth around the world.