In the Arabian Nights, Shahrazad tells of a merman who guides a fisherman around the ocean floor, where underwater societies shun clothing, commerce, and religious restrictions. “I have seen enough,” the fisherman says after eighty days, “for I am getting tired of eating fish.”

The earliest reliable account of human flight concerns a Benedictine monk named Eilmer, who in 1066 fastened wings to his hands and feet, jumped from a tower, and glided more than six hundred feet before falling from the sky and breaking both his legs. He blamed the failure on not having fitted himself with a tail.

Hero of Alexandria invented the aeolipile, a primitive steam engine, in the first century. A hollow sphere with elbow-shaped tubes mounted on an axle and suspended over a cauldron of boiling water, the engine likely could not have powered anything. “It should probably be remembered,” wrote historian William Rosen, “as the first in a line of engineering dead ends.”

In 1965 Stanley Kubrick and Arthur C. Clarke discussed a film project, then called Journey Beyond the Stars. “Science-fiction films have always meant monsters or sex, so we have tried to find another term,” said Clarke. “The best we’ve been able to come up with is a space odyssey,” added Kubrick. “The far-flung islands Homer’s wonderful characters visited were no less remote to them than the planets our spacemen will soon be landing on are to us.”