Chicago: Institute of Applied Science, [1920s]. 19th edition. Pamphlet. 8vo. 21 staple-bound pamphlets without wraps (as issued).
Minor wear to outer pages, with some small chips, closed tears, and fingerprint smudges. A few notations in pencil in margins. Pamphlets are complete, clean, and bound together with string.
This is a complete correspondence course that teaches one to be a Secret Intelligence Operator, which is to say, a private detective. These pamphlets are a publication of the defunct Chicago Institute of Applied Science, which ran from 1916 into the 1970s and mostly published educational forensic science material for the layman, notably the more common A Study of Finger Prints. This course, which covers in 21 lessons the basics of detective work and investigation, was originally sold through magazine ads, a single pamphlet at a time. An absolutely fascinating find, particularly Lesson 12, titled "Portrait Parle" which includes a glossary of slang used by contemporary criminals. The next time you overhear a moll-buzzer say "That Yegg-man in the milky togs belched to the bull-out-of-harness!" you'll have no trouble translating. Very good. Item #1611