Childhood’s End (1953)
Arthur C. Clarke (writer).
Read in 2017.
The futurology is typical of the period, greatly underestimating the rate and importance of computer development in amusingly specific ways. The pacing is good, the artificial suspense not too bothersome, and I enjoyed the Lovecraftian direction the story takes, despite the ridiculous ouija-board scene. There are some significant parallels with At the Mountains of Madness (1936), including the Elder Things being heroic losers of a sort.
References here: “Story of Your Life” (1998).