In case you didn't know, contrails are the ""cloud-strings of condensed apor"" marking the passage of a jet plane across the sky. Since most of these twenty stories were first published in Air Force magazine and deal with the men and planes of the SAC, contrails are also, in this context, ""the slim white flags of freedom"" which ""identify the flying police force that has kept the world safe from the hell a fireball war"". Unfortunately, such phrases are indicative of the level of writing throughout, but it must be admitted that Mr. Miller, an Air Force Reserves major and flight instructor for United Air Lines, does bring a genuine enthusiasm to his material, and oftener than not it proves infectious. If such titles as ""The Man the Axis Couldn't Kill"", ""SAC: The Cocked Fist"", or ""Egg Heads In Hard Hats"" put the reader more in the mood of comic strips like Steve Canyon, well, Mr. Miller makes no secret of his friendship with and admiration for Milton Caniff; indeed, he introduces us to the real-life models of some of Caniff's characters. And even if the book wears a trifle thin in spots, there are at least half a dozen pieces in this collection which make it quite worth while an evening's perusal.