I think the first of his covers that I saw were those of Lin Carter, particularly of the FANTASTIC (in more ways than one) GREEN STAR series. After that, his covers for the novels of Edgar Rice Burroughs, Otis Adelbert Kline and Phillip Jose Farmer exploded my teenage brain cells with excitement, much as N.C. Wyeth and Frank Schoonover had taken my child brain on adventures with King Arthur and Natty Bumppo. It turns out, in an anecdotal sense, that this sort of thing is vital in informing our inner universes; I mean, what would we do without THE TWILIGHT ZONE, THE LORD OF THE RINGS, SHERLOCK HOLMES, TARZAN, or STAR WARS?
The purpose of a cover illustration is to inspire one to read the book; in this sense, in my opinion, Roy was the among best of the best. Below is a selection of his cover work; I can't imagine not being inspired to go online and purchase these great stories!