Written in 1916, the manuscript of this essay lay in Jung's files in Zurich until discovered by students in 1953. It was first published in an English translation by A.R. Pope in 1957, and in the original German the following year. The present publication draws on both. Sonu Shamdasani, editor of the "Red Book," noted that "This paper can be viewed as an interim progress report on Jung's self-experimentation, and may profitably be considered as a preface to Liber Novus."

The paper grapples with the question posed by the philosophy of India, and particularly by Buddhism and Zen: How does one come to terms in practice with the unconscious? Indirectly, it is the fundamental question of all religions and philosophies, for the unconscious is not this thing or that; it is the Unknown as it immediately affects us.

The method of "active imagination," hereinafter described, is the most important auxiliary for the production of those contents of the unconscious that lie, as it were, immediately below the threshold of consciousness and, when intensified, are the most likely to irrupt spontaneously into the conscious mind. The method, therefore, is not without dangers and should, if possible, not be employed except under expert supervision.