Lurking throughout outer space's vast, dark expanses, including the centers of most galaxies, are cosmic monsters that shred and devour any and all stars and planets that stray too close to them. Possessing gravity so immense that even light cannot escape them, they are called black holes. This volume tells how astronomers discovered them, describes these objects' incredibly bizarre properties, and explains why scientists think black holes may exert enormous influence over the future and fate of the entire universe.