John Anthony McGuckin is Nielsen Professor of Early Church History at Union Theological Seminary, and Professor of Byzantine Christian Studies at Columbia University in New York. A Stavrofor priest of the Romanian Orthodox Church in America, Professor McGuckin is the author of more than twenty books on religious and historical themes, including The Orthodox Church (Wiley-Blackwell, 2008), and is widely considered one of the leading experts on Early Christian and Eastern Orthodox traditions writing today.