This is a thin book consisting of six powerful lectures. This is appropriate since Jung's original paper on synchronicity was also a thin but powerful volume. That is the theme here- the connection of the concept of synchronicity with traditional methods of divination. However, do not make the mistake of thinking that divination represents "tame" synchronicity for there is nothing tame or predictable about it.
Von Frantz points out that all traditional civilizations have used oracles to try to ascertain the will of God. Indeed, this is perhaps one of the greatest distinctions between the modern and the traditional. In modern Westernized cultures the approach is to look at an event and then abstract a mathematical model. In traditional cultures one uses an intuitive mental model to read an event. The first way seeks control; the second seeks meaning. Therein lies a vast gulf.
It is pointed out that the unconscious knows things- things of the past and future. This breaks out into the conscious world in dreams and in synchronicity. There is a vast matrix of symbolic meaning in the unconscious and when you energize one nexus, one archetype, other related archetypes sympathetically resonate with it. These resonations break out into the "real" world of the day-to-day conscious in the form of seemingly causeless synchronicity.
It is pointed out that this sort of phenomena occurs mostly to certain "gifted" individuals. The gift consists of a weaker conscious ego that does not get in the way of the unconscious as consistently as it does with the average man or woman. This sort of person can somehow relate more to the absolute knowledge of the unconscious. It seems that it is the bright light of ego consciousness that dims access for others. When the ego is weakened (as in the ego-death of the traditional shaman) then one can dwell on the threshold. Traditionally it is stated that one only learns the secrets of life after dieing, however, if one dies in life and returns then the living can access the secret of the two worlds, of heaven and earth. This is the fenestra aeternitatis, the window into eternity.