India, Dec. 20 -- You hardly need me to remind you that today is the 21st of December. For us in the northern hemisphere, it is the shortest day of the year. Of course, if you live in Australia, New Zealand or South Africa, it is the longest. But those are just calendar details. The fact is I have always been fascinated by this date or bewitched and bewildered by it. For the truth is that the strangest things seem to happen on the winter solstice.

For instance, it was on the 21st of December in 1972, when I was just 17, that I met my first witch. It was at the Christmas fair on Hampstead Heath, a sort of mini winter wonderland. Clutching a hot chocolate, I wandered into a little igloo-like cubicle marked "Occult Powers". Sitting behind a...