Starting in 1913 Jung began a confrontation with his soul and recorded these happenings of his active imagination. Based on these notes; kept in what is known as 'The Black Books' the Liber Novus was created; also known as The Red Book. The Red Book was written between 1913-1916.
The introduction volume will focus on this visionary self-exploration and give a contexualization of later years, from 1916 - 1932.
Note that Jung believed that his fantasies came from general mythopoeic layer of the psyche; as area he called the collective unconscious. There is another writer who may have had similar fantasies; but instead of developing a world of the human psyche, created a world and a place called MIddle Earth.