Grey Lensman by E.E. Smith, PhD.
Part of the classic Lensman series, from which all Space Opera springs. It’s the story of Kim Kinnison, the result of thousands of years of selective breeding by an ancient race, to save civilization from the forces of tyranny. It has massive space battles, planet destroying weapons, intrigue, aliens, battles of the mind, and true love.
Let’s not forget the space axe. Space Armor is proof against bullets and death rays, so the heroes use a specialized 30 pound axe to kill their foes.
A ripping good yarn from the Golden Age of Pulp. SciFi Grandmaster Robert Heinlein considered Smith a mentor, and echos of the Lensman series can be found in Heinlein’s work as well as Ringo, Weber, Halderman, and many others.