Harris-Burland, J. B. The Brown Book (London: John Long, c1923) 254 p.

A wealthy financier, having purchased a library from the estate of Lord Trayle, hires John Hunter to catalog it. Hunter, along with his assistants Flavia Drake and Marion Lorme, discover a conspiracy around a mysterious brown book in the library. It turns out that Lord Trayle's librarian Richard King and his sub-librarian Arthur Rogers were involved.