In the wake of the success of the US paperback editions of J R R Tolkien's The Hobbit (1937) and The Lord of the Rings (1954-1955), Ballantine Books began in 1966 to look for further works to feed the demand for material "in the tradition of Tolkien". During 1967-1968 they reprinted E R Eddison's The Worm Ouroboros (1922) and Zimiamvian trilogy (1935-1958), Mervyn Peake's Gormenghast trilogy (1946-1959) and David Lindsay's A Voyage to Arcturus (1920); Peter S Beagle's A Fine and Private Place (1960) and The Last Unicorn (1968) followed in early 1969. These all sold well, so Betty Ballantine and Lin Carter conceived a regular series to be published "under the sign [logo] of the Unicorn's Head". Carter's nonfiction Tolkien: A Look Behind "The Lord of the Rings" (1969) was a book-length introduction to the tradition of fantasy the series intended to cover; as with the introductions he contributed to each volume, Carter's enthusiasm was infectious but his scholarship suspect.
Beginning in May 1969, with Fletcher Pratt's The Blue Star (1952; 1969), the series brought into print about 60 volumes, many of them reprints of older fantasies, including several each by James Branch Cabell, William Morris and Lord Dunsany. There were also some original works, most notably Joy Chant's Red Moon and Black Mountain (1970) and Katherine Kurtz's Deryni Rising (1970). One of the main achievements of the series was that, after the reprint of her early novel The Virgin and the Swine (1936; vt [in BAF series] The Island of the Mighty 1970), Evangeline Walton was coaxed into finishing the Mabinogion tetralogy – with The Children of Llyr (1971), The Song of Rhiannon (1972) and Prince of Annwn (1974) – which the first volume had all along been intended to initiate.
Carter edited a number of anthologies, with running commentary – beginning with Dragons, Elves and Heroes (anth 1969) and The Young Magicians (anth 1969) – as well as several collections by, among others, Clark Ashton Smith, beginning with Zothique (coll of linked stories 1970). He also wrote another full-length critical book, Imaginary Worlds (1973).
As the series wore on, sales fell off, and it was closed about five years after it began. (Some of the very last volumes, like Prince of Annwn, though acquired for the series were published without the logo or Carter's introduction, so a clear closure-date is hard to determine.) Just a few years later Del Rey Books initiated its own fantasy programme; only a very few of the BAF titles reappeared under the Del Rey imprint. [DK]