THE BLACK STAR PASSES / ISLANDS OF SPACE /            THE MIGHTIEST MACHINE / THE MOON IS HELL                by John W. Campbell                                                                    Ace Books, First Paperback Publication, 1965 - 1973                  Condition: Very Good+ / VG+ to NF (2) / Very Good                                                                                                                         The first two novels were the initial titles in Campbell's Arcot, Morey & Wade series, first published in Amazing Stories in 1930 & 1931.  The third book was first serialized in Astounding Stories in 1934/35.  The fourth book consists of the novel THE MOON IS HELL (1951, original hardback) and the fantasy novella "The Elder Gods" (1939, Unknown magazine).  All are first paperbacks, though MACHINE  is the 1st U.S. pb.  The first three have rather light edge wear (a bit more on BLACK STAR and a small corner crease) and darkening on the cover reverses; the pages have no markings or noticeable wear and the bindings are tight. THE MOON IS HELL has just a little more exterior wear, including a modest spine lean, and darkening on the cover backs, with secure binding and no markings.  A nice collection of Campbell's longer writings, and seldom offered as a set.