Uranus, the seventh planet from the sun, was discovered in the year 1781. But Uranus was not moving the way it was supposed to. Something was wrong. Could an unknown planet be affecting its orbit?

About sixty years later, two astronomers—one English, one French—tackled the problem. Working independently, they calculated the position of what they thought was a planet.

In 1846, two German astronomers proved these predictions correct with the discovery of a greenish-blue planet exactly where it was supposed to be. The mystery of the motion of Uranus had been solved, and the new planet was named Neptune, after the Roman god of the sea.

In the nearly 150 years since its initial sighting, astronomers have discovered many fascinating and unusual things about the eighth planet from the sun, including rings, a giant moon, and a tornado called the Great Blue Spot.

Although we don’t know everything there is to know about Neptune, we do know enough to give us a good idea of its nature. And we know enough to be able to pose new questions that will lead the astronomers of today and tomorrow to a more complete understanding of Neptune, the fourth and last of the great giant planets of our solar system.

Like the slightly earlier Neptune: The Farthest Giant this is a good introduction for young readers to the last of the known gas giants, covering its discovery and what is known about it and its moons. This book tends to be a bit lighter on the statistics and is less colorfully and completely illustrated, however. Teenagers and adults would probably find Saturn and Beyond to be of more interest, even though it was written before Voyager 2 passed near the planet.