Combining in [The 13th Member: A Story of Suspense] the feeling for history found in The Lothian Run … with the proven ability—as in The Kelpie's Pearls …—to create an atmosphere of the supernatural, the author has realized a new dimension in her storytelling. Witchcraft and a plot to destroy James the Sixth … mingle with the dawning romantic awareness of two young people to form a tale of intrigue and passion…. The writing is vivid—almost too realistic in certain of the "examination" scenes—while the personalities and motivations of the characters, both fictional and historical, ring true. The relationship between James and [the Earl of] Bothwell is particularly well drawn…. A controlled piece of writing—intense but not sensational—the book is a literary promise kept and a continuing artistic evolution implied. (pp. 489-90)
Sheryl B. Andrews, "Stories for Older Readers: 'The 13th Member: A Story of Suspense'," in The Horn Book Magazine (copyright © 1971 by The Horn Book, Inc., Boston), Vol. XLVII, No. 5, October, 1971, pp. 489-90.