When an enigmatic monolith is found buried on the moon, scientists are amazed to discover that it's at least 3 million years old. Even more amazing, after it's unearthed the artifact releases a powerful signal aimed at Saturn. What sort of alarm...
Nebula Best Novel winner (1974) Hugo Best Novel winner (1974) At first, only a few things are known about the celestial object that astronomers dub Rama. It is huge, weighing more than ten trillion tons. And it is hurtling through the solar...