"Kill-Bar, the Guide," originally appeared in 1869 as No. 19, Frank Starr's American Novels, with the by-line "Captain Comstock." In two other editions it was assigned to the same author (Pocket Novels, no. 20 and Dime Novels, no. 568), but in Half-Dime Novels, no. 266 and Pocket Library, no. 233 it was reprinted as by "Ensign Charles Dudley Warren of the Engineer Corps." The name "Charles Dudley Warren" sounds too much like the name of the well-known writer, Charles Dudley Warner, to appear true, and it is probably a pseudonym, especially since it was not used until 1882, when Warner was in the height of his fame.

Until the true author is discovered, the three novels under the names "Warren" and "Captain Comstock" are here listed together under the name "Warren" although both names are probably pseudonyms.

Under the name "Captain Comstock" the following novels were published:

Starr's American Novels. Nos. 18, 24, 30
Pocket Novels. Nos. 14, 20, 24
Half-Dime Library. No. 293
Dime Novels. Nos. 563, 568, 572
Boy's Library (octavo). No. 138
Pocket Library. Nos. 266, 430

Under the name "Charles Dudley Warren" the following appeared:

Half-Dime Library. No. 266
Pocket Library. No. 233