[webmaven]

> There is also the choices made by the art directors at the publishers to consider; they were aware of current trends in SF/F book covers, as well as other genres, and would select artists based on how well they worked with those trends. Or against them. Consider for instance Richard Powers (http://www.richardmpowers.com/1970s) who did a ton of psychedelic SF cover work in the 60s, and less work in the 70s as things swung to a more realistic look.

Powers' work definitely evokes that particular era, but (to me at least) it seems a bit... dour, I suppose, and a poor fit for lighter hearted works from then (Laumer's Retief, Harrison's Stainless Steel Rat novels). Definitely a case where ADs were conforming to a trend, although the later examples in those series aren't as jarring.