"They had struggled upwards for a thousand years to reach the point Earth had reached in the early 20th century - and then the revived Galactic Empire took them over as a colony. There was one condition under which the planet's people could achieve freedom - they had to prove they could build themselves a spaceship on their own know-how. The plans for such a starship existed on an even more backward world - heavily guarded as taboo documents. So the puppet king called on his former foeman, Nathan MacKinnie, to go and bring back the "sacred" bluprints - without bringing a world-destroying Imperial fleet on his hands."--Page  cover.
"DAW=sf books."--Cover. Cover art by Kelly Freas. "A serial version of A spaceship for the king appeared in Analog ... c1972."
Source of Acquisition:
Rare Books copy: Purchased from Philadelphia Rare Books and Manuscripts; 2010.