What is an LCCN and do I need one?
The Library of Congress control number (LCCN) is the unique identification that the LOC assigns to the catalog record that’s created for the bibliographic data, or catalog record, of each book in its collection. Each title is assigned a single LCCN (which cover all editions of your book - hardcover, paperback, eBook, Audiobook, etc.)
Many libraries use the LCCN to catalog books. Many books do not have LCCN, and it's possible that some librarians may use this as a reason not to purchase your book.
Once you've published a book, you're required to send a copy to the Library of Congress (LOC). However, given the backlog of books, it may be months before your book is actually put into the LOC.
Once your book is in their system, you can hyperlink directly to the website:
We typically add this to the copyright page:
For Additional Cataloging in Publication Data Block information visit: https://lccn.loc.gov/2015916164
We'll add the LCCN to the copyright page:
Please print the text and the Library of Congress control number (LCCN) exactly as it appears below on the copyright page of this book:
Library of Congress Control Number: [UNIQUE IDENTIFIER]
In order to have your book added to the Library of Congress, you must send a copy of the book with the LCCN noted on the copyright page to:
Library of Congress US Programs, Law, and Literature Division Cataloging in Publication Program 101 Independence Avenue, S.E. Washington, DC 20540-4283
The question we are asking (as of June-2023) is how long after we send in a book does it take to be added to the LOC (and thus have a live link like the example above). I'm waiting to hear a response from my contact at the LOC.
You still might want to get an official copyright (although 80% of authors don't bother).
"Copies sent to the Copyright Office for copyright deposit and registration do not satisfy the LCCN requirement."
You can learn more about how to get a copyright for your book here.