Action, tense personal conflict, realistic dialogue, vivid characters, and exotic locales have made [Zelazny's Amber series] hotly sought by SF fans. However, this third volume [Sign of the Unicorn] takes up the tale with no synopsis and plunges into action so fast that even readers of the first two books may want to check back to refresh their memories. Those unfamiliar with the prior volumes may be completely bewildered. And it all ends with the most dramatic cliff-hanger yet.

Frederick Patten, "Book Reviews: 'Sign of the Unicorn'," in Library Journal (reprinted from Library Journal, February 15, 1975; published by R. R. Bowker Co. (a Xerox company); copyright © 1975 by Xerox Corporation), Vol. 100, No. 4, February 15, 1975, p. 412.