When studying English Civil War tracts years ago as a young research student in the British Museum reading-room in London, where Marx wrote Das Kapital, I used to marvel at the extent of the library’s vast collection of books. But I would also often think about its destruction - and all the knowledge it embodied - in the event of a nuclear holocaust. At that time the Cold War dominated international affairs and nuclear war, we knew, was tantamount to “omnicide” - the annihilation of all life. How did one make sense of this, I wondered: that the several millennia of human history mirrored on the Library’s shelves - the apparent pinnacle, as I then saw it, of four and a half billion years of the Earth’s evolution - could be obliterated in a matter of hours. It was beyond comprehension - though to the millenarian movements I was studying it might have been no surprise.