While leading an expedition through the atmosphere of Jupiter, in the hydrogen balloon craft Kon-Tiki, Captain Howard Falcon discovers a world where bioluminescent air plankton produce brilliant sea-fire, predatory manta-ray creatures dominate the skies, and enormous jellyfish-like beings grow to be over a mile across.

After the success of 2001: A Space Odyssey, Arthur C. Clarke became perhaps the best known living science-fiction writer in the world.