Noll's research concerns mostly the history of Christianity in the United States and Canada. He also teaches courses in the Civil War era, general Canadian history, and the recent world history of Christianity. He is currently working on a book that tries to combine two large narratives about the Bible in American history: first, the rise and decline of a biblical civilization defined mostly by activistic, British-origin Protestants; and, second, the ever widening diversity of Bibles, biblical uses, and other sacred Scriptures in a liberal America open to Christian believers of all kinds as well as the adherents of many other authoritative religious texts
