Masters of the Maze

The Maze is a pathway between worlds and times. Its Masters know the secret but decline to interfere. Its Guardians at different levels prevent invasion of one world by the inhabitants of another. But the alien hive-creatures called Chulpex mean to find their way past the Guardians to colonize a new world, and one ordinary, untrained Earthman is catapulted into wild adventure in his determination to stop them. A classic work by a master of the craft, this is one of Avram's most highly regarded science-fiction novels.