Lots of valuable information here on synchronicity and the archetypal significance of numbers. I admittedly struggled with the first half or so due to the abundance of technical information about mathematics and physics, which I wasn't expecting (kudos to von Franz for her extensive research outside the domain of psychology). The qualitative side of number is so important to our time since we are so one-sided in our quantitative bent which, as von Franz points out, is associated with the death of individuality. I did not realize how consonant the notion of synchronicity is with Jung's whole focus of his psychology, namely the particular, unique individual, who cannot be replicated by a quantitative method. The failure to acknowledge synchronicity then mirrors our failure to admit the significance of the individual, being captured by quantitative thinking. IMO, it is of utmost importance to note that the scientific method would seem, by definition, to preclude the possibility of synchronicity due to its nature as a unique event, "an act of creation," which cannot be replicated. Thus, ignoring synchronicity as though it is merely chance, coincidence or superstition, amounts to writing off the significance of the individual life as chance, coincidence, superstition. Number is not just a unit but a meaning, the same way an individual is not just a social unit, but a meaning. As such, this book brings Jung's work forward in a deep way.