The Clockwork Traitor

Cover art by Chris Foss (Panther Science Fiction, 1978).

Classic space opera adventure, Book #3 in the "Family D'Alembert" series. By law, Princess Edna, heir to the interstellar Empire of Earth, must marry a commoner. But as she travels through her domain, word comes of a mysterious threat to her succession. It's up to Jules and Yvette d'Alembert and their family of circus performers, all agents of the Empire, to uncover this bizarre plot before it can wreak havoc for all of humanity.