Another classic first contact novel. A bit dated (written in 1967) but still a good read.
CRASH LANDING FROM THE STARS---Only three humans would ever know that the blinding flash in the sky on that night in 1982 was an exploding flying saucer. Only they would learn the truth about THOSE WHO WATCH--about the alien beings who came into this world in a crash landing from the stars.
This is the strange, seductive novel of three accidental colonists from outer space whose chance encounter with Earth people is about to trigger interplanetary conflict. It's also a love story.