"Childhood's End" by Arthur C. Clarke
"...however confident they may be in their beliefs, they fear that we will overthrow their gods. Not necessarily through any deliberate act, but in a subtler fashion. Science can destroy religion by ignoring it as well as by disproving its tenets. No one ever demonstrated, as far as I am aware, the non-existence of Zeus or Thor, but they have few followers now. The Wainwrights fear, too, that we know the truth about the origins of their faiths. How long, they wonder, have we been observing humanity? Have we watched Mohammed begin the Hegira, or Moses giving the Jews their laws? Do we know all that is false in the stories they believe?"
"Childhood's End" was first published in 1953, though parts of it were published as a short story, "Guardian Angel," as early as 1945. This novel, in various forms, would be roughly contemporary with Isaac Asimov's first "Foundation" stories, and would predate Frank Herbert's "Dune" novels by two decades.
The novel details the arrival of an alien race, the Overlords, in the year 1975. The Overlords assume stewardship over the Earth and its peoples, ushering in a golden age of peace and prosperity. Humanity, at first straining against the controls imposed by the Overlords, learns to live in harmony with the aliens, and to eventually evolve beyond the aliens' technological superiority.
All of which will sound very familiar to anyone who's read 2001, or any of its three sequels. The difference being that the Overlords of "Childhood's End" endeavor to establish a dialogue between humankind and themselves, to the mutual advantage of both species. The "aliens" (if they can be called that) of the 2001 series are much further removed in terms of time, space, and intelligence, and the mysteries they guard over are only ever glimpsed - much less understood -by the feeble minds of Man.
While I loved the 2001 novels for their scientific accuracy, their prognostication, and the questions they posed, I found "Childhood's End" to be a far more human novel, and in a way far more wide-ranging. "Childhood's End" is rather like the corollary of the 2001 novels, in that it explores many of the same questions from the opposite point of view. Where 2001 begins from "What does it mean to be alien?", "Childhood's End" begins from "What does it mean to be human?" Both questions are, of course, equally valid, but the center of "Childhood's End" is our own, living selves, and this is a much easier place to start from.
Another great thing about this novel is the way in which it seems to anticipate later works, by other authors. As stated above, Asimov was already writing the "Foundation" novels at about the same time, and the following quote from Clarke's work brought those novels immediately to mind.
"A society consists of human beings whose behavior as individuals is unpredictable. But if one takes enough of the basic units, then certain laws begin to appear - as was discovered long ago by life insurance companies. No one can tell what individuals will die within a given time - yet the total number of deaths can be predicted with considerable accuracy.
"There are other, subtler laws, first glimpsed in the early twentieth century by mathematicians such as Weiner and Rashavesky. They had argued that such events as economic depressions, the results of armament races, the stability of social groups, political elections, and so on, could be analyzed by the correct mathematical techniques."
Thus we have something very similar to Asimov's idea of Psychohistory, explained in less obtuse terms. Even Asimov's prescient character, The Mule, is foreshadowed in "Childhood's End," as humanity begins to evolve abilities that put them beyond the Overlords' control. And whereas Asimov spends three volumes (the original "Foundation Trilogy") working through these ideas, for Clarke they are issues of secondary importance, outside the main narrative thrust of "Childhood's End."
There is also this passage, which brought to mind Frank Herbert's "Dune":
"Yet your mystics, though they were lost in their own delusions, had seen part of the truth. There are powers of the mind, and powers beyond the mind, which your science could have never brought within its framework without shattering it entirely. "
In this we have some intimation of a messianic quality within the human race, which will place it beyond the reach of interlopers. The novel even goes on to state that there is an element of prescience involved with the quality, in that mythical archetypes within our human culture have predicted the coming of the Overlords. Seen in this light, humanity's rapid evolution under the Overlords comes to resemble the kind of genetic manipulation seen in "Dune," with the result being a messiah or messiahs who will free humankind from bondage. While Herbert certainly added a host of other ideas to this central concept, it is clear that it had origins at least as old as "Childhood's End."
I could go further, and point out all the other novels that "Childhood's End" seems to anticipate, but if you've read this far you're probably sufficiently interested to read it yourself, and draw your own conclusions. I highly recommend this book, and I'm sure that any fan of the more intellectual science fiction novels will love it.