Freedom's Challenge: Anne McCaffrey

Book III of the Catteni series. The inhabitants of Botany - a mix of humans and extraterrestrials - have managed to building a thriving, productive world out of what had originally been designated a slave planet. Now they planned to overthrow the terrible Eosi who for centuries had existed by subsuming members of the Catteni race, living in their bodies and ruling space through them. The Botantists had received help from the great beings they knew only as the 'Farmers', who had thrown up a huge, impervious space bubble around Botany. Even as the Eosi ships tried to attack, the bubble held firm. But Kris Bjornsen, Zainal and the rest of the Council know they must go out and destroy the Eosi on their own ground. Cover art by Peter Elson.