This book came out well before we had space probes to see what Asimov saw with his imagination. Long before we knew that Jupiter as well has rings, Asimov imagined what looking out is space from several of Jupiter's moons might have been like, if man one day made it that far. Too bad Asimov didn't live long enough to update some of his earlier works to include what probes found out eventually about our largest planet and its many moons. ( )