E. E. Smith 
Skylark Three [EPUB ebook] 

In this exhilarating sequel to the Skylark of Space, momentous danger again stalks genius inventor and interplanetary adventurer Dr. Richard Seaton. Seaton’s allies on the planet Kondal are suffering devastating attacks by the forces of the Third Planet. Even worse, the menacing and contemptuous Fenachrones are threatening to conquer the galaxy and wipe out all who oppose them. And don’t forget the dastardly machinations of Seaton’s arch-nemesis, Du Quesne, who embarks on a nefarious mission of his own. Against such vile foes and impossible odds, how is victory possible?