Mimic by Donald A Wollheim - He walked alone in the dawn and the dusk, and no one knew his name. But the day he perished, and the way he perished–a world will never forget! 

It is less than five hundred years since an entire half of the world was discovered. It is less than two hundred years since the discovery of the last continent. The sciences of chemistry and physics go back scare one century. The science of aviation goes back forty years. The science of atomics is being born.

And yet we think we know a lot.

We know little or nothing. Some of the most startling things are unknown to us. When they are discovered they may shock us to the bone.