“Surprisingly, a problem, undoubtedly not inferior in mystery and unusualness to the most difficult that I have encountered during my long professional career, not only presented itself to me after my retirement, but also, so to speak, turned out to be at my very doorstep. This happened after I shut myself up in my Sussex house and completely surrendered to that peaceful life in the lap of nature, which I so often longingly thought about during the long years spent in the gloomy twilight of London...”