The catalogs in this edition are arranged on the microfilm by company. All catalogs issued by a given company, regardless of changes in its name, are collected under the company heading and are presented in chronological order by date of publication or issue, except in those few cases where difficulties in filming necessitated minor alterations in this order. On a more general level, the companies are grouped into four broad categories: 1) producers and agents primarily active before 1900, 2) producers active after 1900, 3) equipment manufacturers active after 1900, and 4) distributors active after 1900.
The Reel Notes in this guide provide the reader with a complete list of descriptive entries for each catalog and a link to its PDF; these entries are in the same order as material appears on the film. Each entry contains the company name, catalog title and date, page length, any special information about the condition of the copy, and an indication of each institution that has the item in its collections.
Each frame of the microfilm is uniquely identified by an alpha-numeric designation. Each company is assigned a unique letter-code, beginning with A, continuing through Z, and then running from AA to FF. All frames with material under a company heading are then continuously numbered from 001. The combination of letter-code and number constitutes the frame designation, e.g., A-002 or J-963. Using these frame designations, the reader of the Reel Notes can quickly identify the location of any catalog in the edition. These designations appear at the top of each frame on the microfilm. For the convenience of the reader, each frame also has a running head that identifies the company.
On the microfilm, the section for each company begins with a descriptive target that lists entries for each of that company's catalogs. The entries are in the same order as they appear on the film. The target entry for each catalog contains the same information as the entry in the Reel Notes, except that frame designations are not indicated. In some instances, however, the Reel Notes include corrections and additions made after the microfilming was done.
Both the Reel Notes and the targets list entries for each catalog that appears on the microfilm. Certain conventions are followed in presenting information in the entries. When the name of the company on the document differs from that under which it is listed, the variant name is included in parentheses in front of the catalog title. Where information has been editorially supplied, it is given in brackets. All institutions that hold copies of a particular catalog are cited, and each is identified by standard abbreviations (see the Key to Listings of Participating Museums, Archives, and Repositories). The institution that is listed first is the one that provided the catalog or photocopy used in this edition. In cases where an institution holds only a photocopy, its designation appears in brackets. In a few cases, an original could not be located for a particular catalog. In these cases, a photocopy was microfilmed, and in the entry for the catalog this is indicated by an asterisk that appears next to the institutional designation.