For this Ace Double I decided to start with Ray Cummings's The Man Who Mastered Time, which was a reprinting of a book originally published in the 1920s. Cummings was a very prolific author, and though this is the first of his books of his that I've ever read I figured out how he was able to churn out dozens upon dozens of novels over his career, as so far it reads like a cribbing of H.G. Wells' The Time Machine. I'm at the point, though, where, having traveled to the far future and saved the pretty, childlike girl the time traveler (in the case, the inventor's son) communicates with the past to summon reinforcements to fight the bad guys, so we're about to diverge from Wells's story. I look forward to discovering from what source Cummings is borrowing from for the next part of his book,