I added some Toynbee to the last post.
The idea of directed panspermia has had respectable scientific attention, but was popularised by a Swiss charlatan, Erich von Däniken, in Chariots of the Gods? (Erinnerungen an die Zukunft: Ungelöste Rätsel der Vergangenheit), Germany and US, 1968.
He wrote it while manager, from 1964, of the now-demolished Hotel Rosenhügel at Davos. I stayed there for WEF Annual Meetings in the late ’90s when it was run by the much more endearingly eccentric, unforgettable, Eva Ewald and her twin brother. She looked like WH Auden and had grown up something of an anti-Nazi in East Prussia. So I dedicate the last post to her memory.