Holiday reading can be tricky: if you go for something too light, you might run out; if you go for something unknown, it might turn out to be really boring. Of course ebooks can mitigate these risks, by allowing you to defer choices, but I have a pile of dead trees to read. This one came from a work book sale. Normally the books are new releases but sometimes older stock is to be found - this one from 2009.
I thought it was worth a try - after all, the fine structure constant is a weird quantity, and I could see the possibilities for the philosophical side of physics. But in fact, there's next to no physics in the book (and in fact the description of the fine structure constant is initially quite confusing to a physicist used to SI units, as the equation given plainly isn't of a dimensionless quantity). Rather, it is a biography I suspect rather more of Pauli, and rather less of Jung, though there are ample sections on both, and in particular how a relatively short course of treatment led to a lifelong (though World War II inevitably intervened) correspondence and friendship. The exploration of analytical psychology is sufficiently basic for a layman like me with no previous knowledge; without getting terribly enthusiastic, there are some interesting ideas, particularly the way certain themes have recurred in dreams and imagery down the ages. The fine structure constant itself, is left until the final chapter; Pauli couldn't derive its value from first principles, without first knowing other quantities, but searched for Kabbalistic and other numerological theories as to why it should be 1/137, fully aware that he was pursuing a mathematical form of alchemy. Though there isn't any resolution, it's an interesting and approachable read.