In the introduction to the first Volume of her Hainish Novels and Stories she recalls from 50 years earlier::
The first three novels in this volume were published by Donald A. Wollheim, the tough, reliable editor of Ace Books, in the Late-Pulpalignean Era, 1966 and ’67. The first two, Rocannon’s World and Planet of Exile, came out as Ace Doubles: two short novels by two different authors in one paperback cover, like two trains running towards each other on one track. When one train hit the other you turned the book upside down and started from the other end. And Ace Double was a very good deal for under a dollar. It was not a very good deal for the authors, or a brilliant debut in the publishing world, but it paid, it got you into print, it had readers.
And one of them was this high-schooler in Montana named Miles. I loved Ace Doubles because they were well-edited and of reliable quality. And even on my teeny budget I could get whatever ones appealed to me. Of course, the what didn’t occur to me is that, “Yikes, this low price means the writers didn’t get paid scrunt!” I didn’t read Le Guin until the unavoidable The Left Hand of Darkness, but some of my favorites included: James White Second Ending / Samuel R. Delany The Jewels of Aptor (1962); Samuel R. Delany The Towers of Toron / Robert Moore Williams The Lunar Eye (1964); Fred Saberhagen The Golden People / Lan Wright Exile From Xanadu (1964); A. Bertram Chandler Space Mercenaries / Emil Petaja The Caves of Mars (1965); Jack Jardine and Julie Jardine (jointly as Howard L. Cory) The Mind Monsters / Philip K. Dick The Unteleported Man (1966); Lin Carter Tower Of The Medusa / George H. Smith Kar Kaballa (November 1969). I took a pretty extensive break from sci-fi from the time I graduated college until I moved to MA.