The Iver Johnson company doesn’t get much respect or recognition these days, but they made a staggering number of generally very good, inexpensive handguns for many decades. The “cheap” image of the brand has largely prevented a significant collector appeal, and in turn a lack of good research or documentation. The exception to that trend is Bill Goforth, whom I have to believe ignored a great many snickers and jeers and spent a great deal of time and effort amassing a collection of Iver Johnson firearms and studiously researching their history. Mr. Goforth is sadly passed away now, but his knowledge lives on in the book he wrote, entitled Iver Johnson: Arms & Cycle Works Firearms 1871-1993. It is a heavily data-oriented volume, and an excellent resource for identifying and dating Iver Johnson revolvers (its coverage of long guns is minimal).
This was never destined to become a bestseller, but you can still get a copy on Amazon: