I’m reading Synchronicity by Deike Begg. It’s not a book that I sought out; I saw it on the shelf of a friend over the weekend and asked to borrow it (I think, considering the subject matter, one must just come across such books, not look for them).
The term synchronicity was coined by C.G. Jung; he defined it as an “acausal connecting principle.” or, as more coherently defined on Wikipedia:

Synchronicity is the experience of two or more events which are causally unrelated occurring together in a meaningful manner. In order to be synchronous, the events should be unlikely to occur together by random chance.
The concept does not question, or compete with, the notion of causality. Instead, it maintains that just as events may be grouped by cause, they may also be grouped by their meaning. Since meaning is a complex mental construction, subject to conscious and subconscious influence, not every correlation in the grouping of events by meaning needs to have an explanation in terms of cause and effect.
In order to be synchronous, the events should not be causally connected—one should not be the cause of the other, and they should not have an apparent underlying cause.

This is a subject that has fascinated me for some years now because I tend to regularly experience synchronous events. For example, whilst reading and listening to National Public Radio or the BBC, I often read a word and hear it at the same time on the radio (not common words like conjunctions—more often something like “Hindenburgh” or “anachronism”). I have, back in the States, a log of these words (several pages); on a few occasions, it’s happened with entire phrases.

On Saturday, I went to a second-hand bookshop on Great Western Road in Glasgow looking for material on The Golden Ratio (the proportions underlying aesthetics, art, and design across many cultures and ages). A few hours later I was at a dinner where someone brought up the theories of Fibonacci—which are the mathematical implications of the Golden Ratio.

Sunday, on the train to Edinburgh, I read this book whilst listening to music on my iPod. The text mentioned a poem by the 14th Century mystic, St. John of the Cross. Just as I read those words, I listened to the last few notes of Loreena McKennitt’s musical adaptation of the poem. So I was reading a book about synchronous events and had a particularly obscure one doing so; the universe is a fascinating place to be about.