Although American commercial artist Ralph McQuarrie (13 June 1929 – 03 March 2012) was perhaps best known for his work as a conceptual designer for movies and television, including the original Star Wars trilogy (1977-1983), Close Encounters of the Third Kind (1977), the original Battlestar Galactica TV series (1978), E.T. the Extra-Terrestrial (1982), and Cocoon (1985), he was also active, especially in the 1980s, as a cover illustrator for non-movie-related SF paperbacks. Here’s an especially effective example of McQuarrie’s work in that vein, scanned by me from my very own copy of Eric Frank Russell’s Sinister Barrier:

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Keywords: Ralph McQuarrie, Sinister Barrier by Eric Frank Russell.