Originally planned as a brief final volume in the Collected Works, The Symbolic Life has become the most ample volume in the edition, and one of unusual interest. It contains some 160 items spanning sixty years; they include forewords, replies to questionnaires, encyclopedia articles, occasional addresses, and letters on technical subjects. Collection of this material relied on three chief circumstances. After Jung returned from active medical practice, he gave more of his time to writing, and some sixty papers as well as books were written after 1950. Second, recent research has brought to light a number of reviews, reports and articles from the early years of Jung's career. Finally, Jung's files yielded several finished or virtually finished papers that survived in manuscript.

Volume 18 includes three longer works: 'The Tavistock Lectures' (1936); 'Symbols and the Interpretation of Dreams' (1961); and 'The Symbolic Life', the transcript of a seminar given in London in 1939.