Adult admirers of Miss L'Engle will appreciate [A Wind in the Door], her most virtuoso performance in fantasy to date, but I have a lingering doubt if any but the more virtuoso young readers will be able to escape a good deal of bewilderment. The plot is enormously exciting, though I have the same kind of reservations about the solution as some reviewers had about that in Alan Garner's The Owl Service. The book will not be for every child; a good many will find it puzzling, but for the discerning readers who are able to appreciate the symbolism it will make a lasting impression. (pp. 247-48)

Robert Bell, in The School Librarian, September, 1975.