The Book of Unknowing meditates on John's confrontation with the incandescent Jesus, a figure of our desire for immortality. Guiding us through the Gospel's coming to grips with Jesus, the poet David Sten Herrstrom prefers sparking the imagination to arguing a thesis, as he explores John's own obsessions, such as image (light), symbol (water), sign (water to wine), shapeliness (symmetry), loves (Peter, Mary's), and above all, words (the Word, the...