The Cloud of Unknowing, Middle English, late 14th century, author unknown, probably a Carthusian-linked priest: put a cloud of forgetting between yourself and all created things, and beat upon the cloud of unknowing above with the sharp dart of longing love. It taught apophatic prayer to laypeople, a democratizing move.
The modern lineage: Thomas Keating and the Centering Prayer movement rebuilt the Cloud into a 20th-century practice, giving the anonymous manual a second career in parish basements. The technique survived; the austerity got softened for schedule.
The authorship question is the teaching: a book about forgetting the self, unsigned, unclaimed, unrewarded. In an age of branded spirituality, the Cloud's missing byline is either accident or the most complete act of obedience in English literature.
If the author hid himself completely, did he follow his own instructions perfectly?