Apparently Warren St. John was an American author, and the name not a pseudonym. The fact that his novel, "The Quaker Partisan," has the preface dated "Philadelphia, 1869," suggests that he was a Philadelphian. The British Museum catalogue lists him without indicating that the name is a pseudonym, but perhaps this was taken from Allibone, who lists him in the same way, and both based their information on Dime Novels Nos. 52 and 57, where his name was given. It has been suggested that Warren St. John was a pseudonym of Percy B. St. John, but the fact that the two novels published by Beadle under the name of the former appeared in 1863, and that no novel was published by them under the name of the latter until 1869, strongly indicates that they were not the same person. The Saturday Journal (VI, No. 509, February 12, 1876) stated that he "is not a brother of Percy B. St. John."

Dime Novels. Nos. 52, 57, 575, 577
American Library (London). Nos. 28, 31
Pocket Novels. Nos. 27, 29
Boy's Library (octavo). No. 173