History
The popularity of the pocket knife reaches back to the Barlow family, which began making pocket knives in England in the 1600s. In 1785, John Russell began producing the knives in America, changing the name to Russell Barlow.
Identification
For most knives, you can find the manufacturers name or symbol on the master blade of the handle.
Numbering System
Manufacturers of pocket knives use a company-specific numbering system to identify the number of blades, the type of bolsters, the material for the handle, the company pattern and other identifying information. You can find the 4 to 7 digit number on the master blade of the knife.
Expert Insight
Reference books on the topic include "Big Book of Pocket Knives: Identification and Values" by Ron Stewart and Roy Ritchie and "Collectible Pocket Knives" by Dominique Pascal.
Famous Ties
Mark Twain wrote about Barlow pocket knives in "The Adventures of Tom Sawyer" and "Adventures of Huckleberry Finn."