Crisis of Empire is a 1988 military science fiction tetralogy by David Drake and four co-authors, comprising: All four volumes' cover were illustrated by Paul Alexander.

The titular Empire is the Pact, an interstellar polity of four thousand worlds, founded and dominated by humans but incorporating many "signatory" alien species, who are ineligible for citizenship and relegated to menial occupations despite comprising the vast majority of its population.

The book alternates between several narrators, but is mainly told from the point of view of Taddeuz Bertingas, a senior communications bureaucrat in the Aurora Cluster, a Pact province with thirty inhabited planets.

A surprise attack on Gemini by a huge fleet of improvised warships converted from freighters leads to the discovery that the Haiken Maru mercantile conglomerate is conspiring with Aaron Spile, the ambitious governor of neighboring Arachne Cluster.

Senda discovers that a Cernian political faction has made a secret deal with Haiken Maru to draw the planet out of the Pact; Merikur exposes this fact, ending the brutal corporate regime and bringing the rebels over to his side.

The third novel follows a Pact naval officer, captain Allison Spencer, who is dispatched with a fleet of ships to the Daltgeld system, where he encounters an unknown enemy that threatens the whole galaxy.

After losing his flagship to prevent an alien from leaving the system, Spencer and Nanahbuc locate the main asteroid of the enemy and head in with the task force to put an end to it for good.