The publication of his last great work of fantasy, "Merlin's Ring" (third of the series), was also the result of a publisher seeking him. Reprising Wollheim’s role, Lin Carter, editor of the Ballantine Adult Fantasy series, learned of it while enquiring about the availability of the first two Merlin books. In the event, it was issued by Ballantine Books soon after the end of Carter’s connection with the publisher, in the interregnum between the Adult Fantasy series and Ballantine’s new Del Rey Books fantasy series. "Merlin's Ring" explores the Atlantean and Arthurian influences down through history to the time of Joan of Arc. Del Rey later completed Carter’s original intention by reissuing both of the first two books in a single volume with the title of "Merlin's Godson".