What is a numberline?

First Edition Printer's Key
This "1" on this number line shows that this is a first printing

As you delve into the world of book collecting and begin to grasp the basics of identifying first editions and the print runs of collectible books, you are certain to come across something called the “number line,” which is also known as a “printer’s key” or “publisher’s code.”

The number line is a string of numbers printed on the copyright page, and it is used to indicate the print run for the book.  (10 9 8 7 6 5 4 3 2 1)  The lowest number generally indicates the printing of that particular copy.

With each printing of a book, the publisher instructs the printer to remove the lowest number that indicated that run.  The reasoning behind removing the lowest number from the string is that if the printer is only removing one number, they are less likely to make a mistake than if they are introducing a new number each time.

Publishers began using number lines in the early 1940’s, and there is still not an industry-approved, standardized system for this convention.  Therefore, each publisher has its own form of identification.

Some publishers may use ascending number lines (1 2 3 4 5 6 7 8 9 10), others sometimes use letters, and to make matters worse, some publishers may leave the “First Edition” statement on the copyright page but modify the number line to indicate a later printing!

Here’s some industry examples of number line differences:

This is an example of a number line that would indicate the second printing of a book done in 1970:  2 3 4 5 6    73 72 71 70

Here’s a hypothetical example of a number line from an outsourced printer indicating the third print run of a book by Acme Printing Corp. done in 1996: 3 4 5 6 7 8 9 10   APC   00 99 98 97 96

Random House is a notable exception to the basic number line.  For a period of several years, they indicated a first printing with a number line that began with “2”.

Anness Publishing uses a number line that reads 1 3 5 7 9 10 8 6 4 2. The 1 indicates that this is a first printing. This same number line in a third print run would look like this: 3 5 7 9 10 8 6 4.

The number line can provide some useful information if you know how to read it. When it all comes down to it, the best way to know that you are purchasing a true first edition, first printing is to get a guide to identifying first editions with descriptions of number lines and other identification points for each individual publisher. 

Image credit:
Travelin Librarian

This entry was written by and posted on December 21, 2010 at 10:58 am, filed under Book Collecting, Book Identification and tagged , , , , , , . Bookmark the permalink

4 Responses to “What is a numberline?”

  1. Seabird Designs

    … Biblio.com…

    […] Find More Informations here: biblio.com/blog/2010/12/what-is-a-numberline/ […]…

  2. David D.

    I had been trying to decypher the numberline on my book but I get confused.. the line is 115505 could anyone possibly help me figure this out?.. Hemmingway was always a favorite but Id like to know if this book might be a first edition.

  3. Alison Barnes

    What does the printer’s key 003 represent?


Leave a Reply