Edmond Hamilton 
Corsairs of the Cosmos [EPUB ebook] 

Machines from a dying galaxy arrive with a bold plan: steal suns from our galaxy to revitalize their own. When the Interstellar Patrol fails to stop the mechanical corsairs from dragging away twenty suns, Captain Dur Nal and his crew devise an audacious counterattack. Commandeering one hundred dark stars of their own, they launch a daring mission across the void to reclaim their stolen suns and strike at the heart of the machine civilization. But in this cosmic game of tug-of-war with entire stars as the prize, the fate of two galaxies hangs in the balance