SF A. E. van Vogt The Far-Out Worlds of A. E. van Vogt (1968) H-102 SF Edward E. Smith Subspace Explorers (1968) H-105 SF James H. Schmitz The Demon Breed (1968) K Series K-154 SF George R. Stewart Earth Abides (1962) A Series Ace Books published its A series of books from about 1966 to 1968, priced at 75 cents. A-3 SF Bernard Wolfe Limbo (1966) A-4 SF J. R. R. Tolkien The Fellowship of the Ring (1966) A-5 SF J. R. R. Tolkien The Two Towers (1966) A-6 SF J. R. R. Tolkien The Return of the King (1966) A-8 SF John Myers Myers Silverlock (1966) A-10 SF Terry Carr and Donald A. Wollheim (eds.) The World's Best SF: 1967 (1967) A-12 SF Terry Carr (ed.) New Worlds of Fantasy (1967) A-13 SF James H. Schmitz The Witches of Karres (1968) A-15 SF Terry Carr and Donald A. Wollheim (eds.) World's Best SF: 1968 (1968) A-16 SF Alexei Panshin Rite of Passage (1968) A-17 SF Avram Davidson (ed.) The Best From Fantasy & Science Fiction, 14th Series (1968) A-19 SF Piers Anthony and Robert E. Margroff The Ring (1968) A-25 SF Edgar Rice Burroughs The Outlaw of Torn (1968) A-29 SF James Blish and Norman L. Knight A Torrent of Faces (1968) N Series N-3 SF Frank Herbert Dune (1966) References Ace Image Library. Contains images of most covers for both the singles and doubles. Tuck, Donald H. The Encyclopedia of Science Fiction and Fantasy: Volume 3, Advent: Publishers, Inc., 1982. . Lists all ACE sf titles, single and double, published through 1968. The following references have not been seen: Peters, Harold R. Science Fiction, Fantasy & Horror in the Ace Letter-Series Editions: A Collector's Notebook, Silver Sun Press, 1996. Ace SF letter-series single titles SF letter-series single titles Ace SF letter-series single titles