Mark F. Fischer is a professor of theology at St. John's Seminary, the seminary of the Roman Catholic Archdiocese of Los Angeles. He joined the seminary faculty in 1990. He is the past chairman of the Ecclesiology Seminar of the Catholic Theological Society of America and is webmaster of the Karl Rahner Society.
His website devoted to Foundations of Christian Faith is one of the most visited websites in the world for information on Karl Rahner. Mark is married and has three sons.