Guy Erwin is a church historian and ELCA pastor and teaches at California Lutheran University. Born on the Osage Reservation in northeastern Oklahoma, educated at Harvard and Yale in the USA and Tübingen and Leipzig in Germany, he enjoys crossing cultural boundaries, considering the ways ideas have changed over time, and exploring new points of view.

Guy teaches general courses on the History of Christianity as well as more specialized ones on Luther, Augustine, and World Lutheranism. But his main love is learning about the first centuries of Lutheran church life in Germany and Scandinavia. He has led many tours to the Luther sites as well as other landmarks of Christian history in Europe.