The Midwich Cuckoos
By John Wyndham
I remember watching the film Village of the Damned on television when I was quite young and liking it: scary and unsettling. I wish I had read the book it was based on sooner. The film makers did a fairly good job if I recall but the book is better.
Set in a very small English village, Midwich, the whole population has a very mysterious episode where everyone becomes unconscious for a day. A few weeks later, the women discover that they are all pregnant and give birth to "The Children" (the cuckoos of the title). The "Children" (always capitalised in the book) are unusual: precocious, golden eyed and with powerful mind control capabilities. They seem to share a consciousness, the boys separate from the girls. Definitely not human. As they grow and become teens, the full reality and danger of their existence becomes manifest as they protect themselves in a way we cannot fathom or resist.
The villagers take to calling this episode of unconsciousness, the Dayout.
The characters are mostly the sort Wyndham seems to use in his books: middle class and with a common-sense intelligence and capability. The Children are not what they seem but people have a hard time seeing past their appearance. It is a horrifying state of affairs for all, but particularly for the "host mothers", who know the children are not theirs but sometimes have to struggle with their human instincts. Horrifying and unsettling, a situation that is understood clearly by some, particularly an older writer Gordon Zellaby. This might lead to nothing less that the replacement of the human race as masters of the planet.
At heart, a first contact story, it is never actually determined who the Children are or where they come from. This is a book with a great idea and lots of discussion about the ramifications for humanity. I thoroughly enjoyed it.