Bernard McGinn is one is of the greatest living authorities on Catholic historical theology. The Naomi Shenstone Donnelly Professor (Emeritus) of historical theology and history of Christianity at the University of Chicago, McGinn holds a Ph.D. from Brandeis University and an S.T.L. from the Pontifical Gregorian University. McGinn has lectured on and written extensively about the history of apocalyptic thought and recently has focused his attention on the fields of spirituality and mysticism. His current long-range project is a seven-volume history of Christian mysticism in the West called The Presence of God.

"This is an engagingly written book on a topic little studied. One could learn a good deal about the history of theology while finding clues for further reading in McGinn's fine bibliographies." --Lawrence Cunningham, Commonweal magazine