He was among the earlier Western European beneficiaries of this Tibetan Buddhist Scripture/ Dharma of the Death, Bardo, and Reincarnation, and realized immediately its significance.
When Jung writes of the collective unconsciousness, the symbols and mandalas related to dreams, one wonders was in fact Jung not a Buddhist? Of course, one can look at Jesus Christ, and wonder if not in fact was he not a Buddhist?
Ignoring the double negatives above, we come to the point. Jung was perhaps the most recognized and influential Western Medical Doctor who took seriously the writings, philosophy, and science coming from another part of the world than their own, and worried not what effect it had on his professional reputation to write of their significance.
There are many tangents we can go on from here, and perhaps we will, but we’ll only note here how things go in real life, that aren’t so planned in one’s career, or what one would prefer not to think about, such as world wars and madmen who run them them. We’ll ignore them for now, but for anyone too much in a hurry, read or watch the film “Seven Years in Tibet.”
Perhaps the best thing to write up front, before delving into Jung’s interpretation of “TTBD” is that one should go directly to the source document, instead of relying on someone’s interpretation of the book, be it Jung’s or mine (being here largely an interpretation of Jung’s interpretation!). The Illustrated TTBD is rather a good place to start, and should proceed any further discussion. Perhaps you are familiar with this book, and Jung’s interest in it to the point where the book would always be with him, both physically and mentally. Better still would be of course taking refuge in the Three Jewels, having a qualified teacher of who to ask questions, and motivated Sangha with which to share. As opportunities, present, we avail ourselves best we can!