Arthur C. Clarke is best known as the author of 2001: A Space Odyssey, which served as the basis of the Stanley Kubrick film of the same name. Childhood's End (1953), while never made into a movie, bears many hallmarks of that classic piece of science fiction: deep philosophical questions about mankind's destiny and evolution, a detached, almost impersonal tone, mysterious but benevolent aliens, and an examination of man's relationship with science and technology. While I can't say it's the most exciting book I've ever read, it's a serious piece of hard sci-fi that poses some fascinating ideas and questions.
The Cold War is at its peak. American and Soviet scientists pour their efforts into a nationalistic, competitive space race. All that changes when the Overlords arrive. Lead by the "supervisor" of the earth, Karellan, this race of beings positions ships all over the world and puts an and to war, famine, poverty, disease, and the petty concerns that have overtaken human society. This leads to a golden age for humanity, no more war, and no more suffering. But the Overlords are preparing the human race for something. They answer to a higher power.
Clarke writes his novel almost like it was a news report or scholarly essay (minus text citations). He tells rather than shows. The result is a very cerebral book. To Clarke, sci-fi is not a gimmick for adventure or satire; it's an examination of a point and a serious argument. There are characters, but they exist symbolically to reflect a certain part of the Clarke's thesis. That does make for dry reading, and it takes a while to get used to, but the book feels a historical account rather than a piece of pulp fiction. It's strangely plausible, thought-provoking and at times, frightening.
Human knowledge has its limits. The Overlords have long mastered mankind's achievements, and they could destroy everything if permitted. Their appearance is built up, and while it is inevitable the reveal would somewhat be anticlimactic, it's still pretty effective. They could be anything, even something completely beyond human comprehension. Humans are essentially the children of the universe, in need of guidance before they can fully mature. What that level of maturation is is unsettling.
Clarke's greatest asset is strict logic and utter seriousness to his subject. He has a hypothesis and sees it through to its final destination. He did that in 2001 with a computer on a trip to Jupiter with astronauts, and he does it here with the human race on earth and its benefactors. It's not Star Wars, that's for sure.