The Imperial Stars is a science fiction novel by Stephen Goldin expanded from a novella by E. E. "Doc" Smith.

The D'Alemberts are natives of the high gravity planet DesPlaines, giving them unusual strength, speed and coordination.

They put this to good use by operating the "Circus of the Galaxy," a spectacular combination circus/mobile amusement park famous in every inhabited system, entertaining millions and rarely visiting the same planet twice in an average lifetime.

Managed by the reigning Duke, who is absolute ruler of DesPlains and head of the D'Alembert family, the circus is a proving ground for the best agents available and can provide a cadre of highly skilled professionals in many fields, as needed.

So when the Circus is summoned to Earth it is time for Jules and Yvette D'Alembert, brother and sister Imperial Stars, to leave their place in the spotlight under the big top to their successors, and become what they were always meant to be: the Empire's top secret agents.