The Cloud of Unknowing is an anonymous work of Christian mysticism written in Middle English in the latter half of the 14th century. The text is a spiritual guide on contemplative prayer in the late Middle Ages.

The work had already become known to English Catholics in middle 17th century, later ascetic and Benedictine mystic, Augustine Baker (1575–1641), wrote an exposition on its doctrine. Today a transcript of the work dated 1677 is at the Ampleforth College at the British Library. Manuscripts of the work are today at British Library and Cambridge University Library.

Anonymous English Monk on Know Thyself

“It is on your own self-knowledge and experience that the knowledge and experience of everything else depend.” ~ From The Cloud of Unknowing

The book counsels a young student to seek God, not through knowledge and intellection (faculty of the human mind), but through intense contemplation, motivated by love, and stripped of all thought. This is brought about by putting all thoughts and desires under a “cloud of forgetting”, and thereby piercing God’s cloud of unknowing with a “dart of longing love” from the heart.

Further Reading:

Bernard of Clairvaux on Know Thyself
Geoffrey Chaucer on Know Thyself
Nazarius of Valaam on Know Thyself