All about Eastern Christianity and Jewish Mysticism
Apparently, the practice of the Jesus Prayer is extremely ancient, even more ancient than Jesus himself! Or rather, the mantra-like repetition of the name of God has its roots in Judaism. You can read all about it on a page put up by Father Alexander Golitzin, a professor of theology at Marquette University, and also the former teacher of Mrs. Athanasius.
I'm downloading a work on Apraphat, the Persian Sage by said Fr. Golitzin this very minute. It should be some good Thanksgiving reading.
P.S. My wife tells a story about class with Golitzin: she was very quiet in the class, and Fr. Golitzin didn't know who she was. Then they took the first test, and Mrs. Athanasius, as usual, aced it. Fr. Golitzin asked a question in the next class: "Who can answer this? How about, oh, Miss Smith (not her real maiden name)?" Thus he found out who the smart quiet girl was.