Here is my reasonably faithful large assemblage of the cover art for the 1971 Ballantine U.S. paperback edition of The Dream-Quest of Unknown Kadath, in the Ballantine Adult Fantasy series. The spine could only be had as a low-res scan, which is why that bit is fuzzier than the rest.

The book went through three paperback printings from Ballantine before 1975, as the USA’s baby boomers came of age and discovered Lovecraft and fantasy in general. By 1983 the Del Rey edition had galloped like a frisky zebra through 28 reprintings. Given such apparent popularity at that time, it’s a pity so few young writer cut their little kitty teeth on Lovecraft’s Dreamlands. Gary Myers’s fine The House of the Worm (1975) collection being the stand-out exception. As C.W. Thomas wrote, back in 2010 at Innsmouth Free Press…

It saddens me a little that the Dreamlands never caught on as a setting for other writers. This seems odd, considering how much of what Lovecraft wrote became the springboard for new authors. … My challenge to writers is simply to write a tale of Ulthar or lost Kadath. Forget the retread tales of Deep Ones, the diaries about guys who look for Cthulhu. Try a little magic, instead. I will gladly join you in the land of Mnar, where men built “Thraa, Ilarnek, and Kadatheron on the winding river Ai.”

The Ballantine cover art for the 1971 Dream-Quest was by Gervasio Gallardo (Gervasio Gallardo Villasenor, of Barcelona, Spain). He had a solo 95-page artbook in 1976, The Fantastic World of Gervasio Gallardo, and a feature in Novum in the early 1970s, “Gervasio Gallardo, Spain: a master of free and applied art”.

An example of his other 1970s work can be seen below. This picture was made at a time before the crude political usurpation of the Marian ‘crown of stars’ by the mundane European Union, and the symbolism here is rather in his blending of the Catholic Mary ‘star of the sea’ with the classical Venus. Though such a comparison was likely to have gimlet-eyed Jesuits leaping out at the artist from dark corners of Barcelona’s Gothic Quarter, it was and is a perfectly valid elision to make and rests on good historical foundations — it was not a made-up New Age hippy confabulation of the mid 1970s. The devout Christian C.S. Lewis had also felt free to make a similar elision at the end of one of his science-fiction novels, as a way of of introducing the Marian in a form palatable to his readers.

Born in 1934, the artist Gervasio Gallardo came-of-age in the Catholic Francoist post-war Barcelona of the mid 1950s. He left Spain for work at a German studio in 1959, moving later to an agency in Paris and then to USA in 1963. He was prolific in the early and mid 1970s, producing many covers for the Ballantine Adult Fantasy series and other authors. Thereafter he went back to Barcelona and set up his own studio, and then appears to have worked mostly as a commercial artist, with clients among European perfumiers and the makers of fine Spanish liqueurs and brandies. Not a bad line of regular work to be in, as the boom years of the mid-1980s approached.

The Fantastic World of Gervasio Gallardo at Archive.org.