The Sargasso of Space and Two Others / The Copper-Clad World (Wildside Double)

In the tradition of the old "Ace Doubles" two-in-one books (flip one over to read the second title) -- here is the first Wildside Double . . . "The Sargasso of Space and Two Others," by Edmond Hamilton and "The Copper-Clad World," by Harl Vincent. Two oldtime science fiction authors at their galaxy-spanning best!