The Cloud of Unknowing draws on the mystical tradition of Pseudo-Dionysius the Areopagite and Christian Neoplatonism,[2] which focuses on the via negativa road to discovering God as a pure entity, beyond any capacity of mental conception and so without any definitive image or form.

[3] Concerning the placement of The Cloud of Unknowing in the trends of the Catholic Church at the approximate time of its writing, the work joins a broader medieval movement within Christianity toward a religious experience of a more individual and passionate view of relationship with God.

It is less than half the length of the Cloud, appears to be the author's final work, and clarifies and deepens some of its teachings.

This relationship between God and the contemplative takes place within continual conflict between the spirit and the physical.

The Cloud of Unknowing is written specifically to a student, and the author strongly commands the student in the Prologue, "do not willingly and deliberately read it, copy it, speak of it, or allow it to be read, copied, or spoken of, by anyone or to anyone, except by or to a person who, in your opinion, has undertaken truly and without reservation to be a perfect follower of Christ.

"[8] The book counsels the young student to seek God, not through knowledge and intellect (faculty of the human mind), but through intense contemplation, motivated by love, and stripped of all thought.

This form of contemplation is not directed by the intellect, but involves spiritual union with God through the heart: For He can well be loved, but he cannot be thought.

"[10] The author draws a strong distinction in Chapters 16-22 between the active and contemplative Christian life.

"[8] While the author holds Mary as the superior example in the passage as a "model for all of us [who seek to be contemplatives]," he clarifies that Martha's activity in service to God was nonetheless "good and beneficial for her salvation" but not the best thing.

Do not consider any particular virtue which God may teach you through grace, whether it is humility, charity, patience, abstinence, hope, faith, moderation, chastity, or evangelical poverty.

"[16] While the practice of contemplation in The Cloud is focused upon the experience of spiritual reality by the soul, the author also makes some provision for the needs of the body, going so far as to say that care for the body is an important element of spiritual contemplation if only to prevent hindrance of its practice.

For I tell you that this work demands the greatest tranquility, and a state of health and purity in body as much as in soul.

[7] This work became known to English Catholics in the mid-17th century, when the Benedictine monk Augustine Baker (1575–1641) wrote an exposition on its doctrine based on a manuscript copy in the library of the monastery of Cambrai in Flanders.

[2] The work has become increasingly popular over the course of the twentieth century, with nine English translations or modernisations produced in this period.

The practical prayer advice contained in The Cloud of Unknowing forms a primary basis for the contemporary practice of Centering Prayer, a form of Christian meditation developed by Trappist monks William Meninger, Basil Pennington and Thomas Keating in the 1970s.