Mystical union in Judaism, Christianity, and Islam

Mysticism is a tricky subject for serious academic inquiry. The difficulty of making an intellectual argument about the ineffable is the most immediate obstacle. This is further complicated by the fact that many who are interested in the subject like to argue that all mystics experience a universal union with the ultimate, a proposition that is hard to reconcile with a scholarly concern for specific context, language and sources. Especially in the early part of the 20th century, under the influence of Evelyn Underhill, students of mysticism tended to place all interpretations into a pre-articulated framework of "the mystic way." -- From http://www.jstor.org (Sep. 5, 2014).