In 1980 and 1981 author, fan, reviewer, and comics expert Richard A. Lupoff published two anthologies for Pocket Books with the description "stories that should have won the Hugo." Beginning with 1952, Lupoff chose one story from each year that he felt had been unfairly overlooked or denied the prize for some political or editorial reason. Lupoff selected stories for four volumes, but the series was cancelled after the second, due to poor sales, as Lupoff explained years later when he finally published volume 3.
Meanwhile, Mike Ashley assembled The Illustrated Book of Science Fiction Lists in 1982 (the 1983 US edition is shown in the photo) and asked Lupoff to extend his list backward and forward, resulting in selections running from 1926 to 1978 (pp 90-91 of the US edition). The entire list is included here (though of course the stories themselves are not in Ashley's book).
Lupoff's three books are notable not so much for highlighting stories that might well have been award-winners as for Lupoff's detailed introductions, reviewing the other nominees and providing a summation of the state of the SF field for each year, much as Gardner Dozois would do at much greater length in his annuals.
Lupoff never selected more than one story per author.