LEGO customer catalogs have been produced by TLG almost continuously since 1949. Until 1965 they were more or less just a single piece of paper, sometimes folded, other times not. All of these early catalogs were either printed in Denmark or Germany. And the design/layout of these early catalogs greatly varied from year to year.
The first year of LEGO... 1949-50... there were only 5 LEGO items produced... 3 basic sets (700/1, 700/2 and 700/3), and 2 spare parts pack (700A 2x2/2x4 Automatic Binding Bricks, 700B Automatic Binding Bricks windows/doors.
The inside of this folded catalog shows the earliest known image of LEGO buildings and models....
As far as I know... there is only one known example of this 1949-50 catalog image, and this is not in the possession of the Billund Archives. I would value this rare survivor into the thousands... $$$
From 1950-53 TLG produced a pair of 8 sided long strip Automatic Binding Bricks catalogs. here is the 1952-53 version, which displays both "Automatic Binding Bricks" and for the first time "LEGO Mursten" (LEGO Bricks).
In 1953 TLG switched from calling their product from "Automatic Binding Bricks" over to "LEGO Mursten". However, there were no true LEGO catalogs or price guides produced in 1953. The only item that fills in the gap for 1953-54 is this page from a Danish LEGO Retailer Catalog....
My LEGO collectors guide has an entire huge chapter devoted to early LEGO catalogs, an unbroken list from 1949-65.
More to come.... ;-)