The R L Polk Company is one of a kind. They made numbers their business, and they never strayed from it. Numbers and names in a population Census, Assigned a credit rating for every adult in the land, Every Business in America, Telephone Numbers for every Phone # in America plus addresses. If a Company or private citizen paid their bills in a timely fashion it was recorded as such. If they didn't, same thing. A given company could subscribe and received a book for the region desired. Pick up that little book, turn to Westby Mercantile Clayton, Washington, and there was the rating for all to see. Probably A1. If it read AA1 it was a larger business, AAA1 as big as they get. The 1 depicted 'prompt' 11 Satisfactory and on and on.