Kurt Vonnegut once said of Arthur C. Clarke's novel Childhood's End that it is one of the few masterpieces of the science fiction genre.
The plot starts as many sci-fi stories start. A fleet of alien UFOs descend from space and park themselves over the major cities on Earth. However, there is no attack. There are no lasers fired, nor any swathes of destruction. The aliens, it seems, are benevolent. They are here to help guide humanity through this stage of potential peril. Remember, Childhood's End was written in 1953, during the height of nuclear tension.
Nobody ever sees the aliens, however, except for one individual. Their plans are kept equally secret, but slowly and with deliberate guidance they build the trust of humankind. By the time they are physically revealed, around the halfway point of the book, it becomes apparent why they were so secretive. They are the very image of the devil - red skin, horns, a pointed tail, and leathery wings. However, since they had shown their goodwill through the years, little was made of their “coincidental” resemblance to an ancient symbol of evil.
The narrative was initially a bit difficult to follow, as it moved around through time, following a different cast of characters at each step (only occasionally revisiting previously introduced characters). The humans are drawn quite flat, but they serve mostly as two dimensional vehicles to tell the larger story... one that culminates in a series of heady revelations.
I particularly like the racial memory (or racial premonition) ideas and the ideas of collective consciousness, and how this might relate to our civilization's coping of life with the Internet - something Clarke certainly could not have imagined in the early 1950's. I enjoyed how he plays with time, whether it's through the narrative that spans about 150 years, or when he describes the effects of near light speed travel and time dilation. Every aspect of this novel is crafted masterfully, so it's easy to understand why many consider it a landmark of its genre... and why it may be one book I return to again in the future.