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 underlying message of this work suggests that the way to know God is to abandon consideration of God's particular activities and attributes, and be courageous enough to surrender one's mind and ego to the realm of "unknowing", at which point one may begin to glimpse the nature of God.

Evelyn Underhill (1875 – 1941) was an English Anglo-Catholic writer and pacifist known for her numerous works on religion and spiritual practice, in particular Christian mysticism.