re: Covers
that's exactly what I meant .. but gravitational lensing only became a 'hot topic' in the 1990s after the launch of Hubble made such observations possible. To think that this was not only anticipated, but actually turned into a story, in 1940, is really incredible. GR was only 20 or so years old at the time, and barely understood in academia let alone in the popular media.
These writers and illustrators really are our ancestors, if you get my meaning.