Once you have your ISBN numbers in hand you can apply for a Library of Congress Control Number. The process is quick and easy, and it begins with an online visit to www.loc.gov/publish/pcn.
The initial information you’ll have to submit concerns your name, email address, phone number, publishing house, and other basic information. Your application submission should get a prompt email reply stating: “We have received your request to participate in the Preassigned Control Number (PCN) program.”
In my case, the US Copyright Office very quickly provided me with the account number and a temporary password, so I was immediately able to log into the account and provide all of the required information concerning myself as well as my book. After submitting this information I then got an email notification advising that my submission “was successfully transmitted to the Library of Congress.”
After only two to three business days, I got my Library of Congress Control Number.
I next sent a copy of my book’s full text, artwork and illustrations to the Library of Congress.
It’s important to note that you’ll need to apply to the US Copyright Office for a LCCN well in advance of printing your book, because it must appear on the copyright page of your book. I applied two months before my projected printing date, and as mentioned I got the number rapidly.