Stark and the Star Kings, by Edmond Hamilton and Leigh Brackett

It's a collaboration between husband-and-wife team of Edmond Hamilton and Leigh Brackett. Hamilton's name is first on the cover, but I dare say there is more Brackett in the story than Hamilton.

John Eric Stark (who I'm told has his own series of stories) is sent into the future to the universe of the Star Kings to battle a great destructive entity that threatens to destroy all life in the universe. It's a decent story, albeit shorter than I'd like. Interesting--usually I complain that stories are too long.