An LCCN, or Library of Congress Control Number, is a number that the Library of Congress assigns to titles it’s likely to acquire. If you want the opportunity to have your book in the Library of Congress, you’ll need an LCCN, which will be placed on the copyright page and look something like this: “Library of Congress Control Number: 2001012345”.
Only U.S. book publishers are eligible to get an LCCN, however. This is because the publisher, whether that’s you or someone like Mill City Press, must have an editorial office in the country in case someone needs to answer questions about the book.
How Do You Get an LCCN?
To get an LCCN, you have to apply for one before your book is published. Once you receive your LCCN, that number is printed with the copyright information. Once your book’s been published, you’ll have to send one copy of the best edition to the Library of Congress. The best edition is a paperback or hardcover—ebooks are ineligible for an LCCN, even if their print version has one.
Read more about LCCNs on the Library of Congress’s page on Preassigned Control Numbers.