Terror Keep is an exceptionally effective and thoroughly entertaining thriller, featuring perhaps the most memorable of all Wallace's heroes, Mr. J. G. Reeder. Reeder is at pains to point out that he is not a detective, which is technically true. He is not a policeman, and has no power to arrest suspects. He works as an investigator of banking crime, particularly forgery. This time detective JG Reeder and his attractive secretary, Margaret Belman, almost suffered the wrath of John Flack, an unusual villain who pairs maniacal insanity with genius. Detective and criminal are well matched and the reader is kept in the dark about the outcome of this deadly duel for a long time.