Karen Armstrong spent seven years as a Roman Catholic nun in the 1960s, but then left her teaching order in 1969. She studied English Literature at the University of Oxford, earning the degrees of B.A. and M.Litt.. Since then she has taught modern literature at the University of London, and headed the English department in a girls' public school. In 1982, she became a full time writer and broadcaster.
Her television work has included The First Christian, a six-part documentary series on St. Paul, which she wrote and presented  and two interview series: Varieties of Religious Experience  andTongues of Fire . She now regularly appears on radio and television to comment on religious affairs in England and the United States, is a frequent contributor to conferences, panels, newspapers and periodicals on both sides of the Atlantic and is a regular columnist for the Guardian newspaper.
For ten years, Karen Armstrong taught part-time at the Leo Baeck College for the Study of Judaism and the Training of Rabbis and Teachers. Since September 11th, however, she has become chiefly known for her work on Islam and Fundamentalism, particularly in the United States. She has addressed members of the United States Congress on three occasions, has participated in the World Economic Forum in New York and Davos, and was one of three scholars invited to speak in the United Nations in the first session ever devoted to religion in that body. She has recently been appointed to the United Nations initiative "The Alliance of Civilizations".
Her books include: Through the Narrow Gate, an autobiographical work ; The Gospel According to Woman ; Holy War, The Crusades and their Impact on Today's World ; Muhammad, A Biography of the Prophet ; A History of God , which became an international bestseller; Jerusalem, One City, Three Faiths ; and In the Beginning, A New Interpretation of Genesis ; The Battle for God, A History of Fundamentalism ; and Islam, A Short History ; Buddha (2001); The Spiral Staircase: A Memoir (2004); A Short History of Myth (2005): The Great Transformation: The Beginning of Our Religious Traditions (2006). She has recently revised her biography of Muhammad, which has just been published under the title: Muhammad, A Prophet for Our Time.