These three get sold together as "registration services", usually for a few hundred dollars, usually to authors who do not know that one of them is free, one costs $45 and the third is the only one that matters. Here is what each does, what it costs, and the honest answer to "do I need it".

ISBN: the one you need

What it is. A 13-digit number that identifies one edition of one book in one format. Paperback and ebook are two editions, so two ISBNs. A second edition with real changes is a third. A reprint with a typo fixed is not.

Who issues it. In the United States, Bowker, and only Bowker. In Spain, the Agencia del ISBN. Anyone else selling you one is reselling.

What it costs. Bowker: $125 for one, $295 for ten, $575 for a hundred. The ten-pack is the sensible buy if you plan more than one book; two formats of two books already uses four. Spain: €45 per edition as an author-publisher, or €95 for ten if you register as a publisher.

The free one. Amazon KDP gives you an ISBN at no cost. The catch is in the metadata: the publisher of record becomes "Independently published", and that ISBN can only be used on Amazon. If you later want the book in Barnes & Noble, a library or a Spanish bookshop through Ingram, you need a second ISBN, and now the same book exists twice in the databases. Buy your own from the start and use it everywhere.

Do you need it? Yes, for anything sold in a shop. The only book that does not need one is a PDF you give away from your own website.

The barcode. Bowker will sell you one for $25. Do not buy it. Your cover designer, KDP and Ingram all generate it from the ISBN for free.

LCCN: free, useful, and often done wrong

What it is. A Library of Congress Control Number. It is a catalogue number, not a legal protection. It lets American libraries find and order your book through the standard channels. Without it, a librarian who wants your book has to create the record by hand, and most will not.

What it costs. Nothing. It is issued through the Preassigned Control Number program at the Library of Congress.

The rules that trip people up.

• You apply before publication. Once the book is out, it is too late for that edition.
• The book needs a U.S. place of publication on the copyright page, and the publisher needs a U.S. address.
• Ebook-only titles are not eligible. There has to be a printed edition.
• After publication, you send one printed copy to the Library. That is the deal.
• If the publisher of record is Amazon (because you used the free ISBN), you cannot apply. The LCCN is one more reason to own your ISBN.

Do you need it? If you want libraries to carry the book, yes, and it costs you a copy and ten minutes. If you only sell on Amazon, it changes nothing.

Copyright: you already have it

What it is. The legal right to your own text. In the United States, in Spain and in every country that signed the Berne Convention, you own the copyright the moment you write the words. You do not need to register, pay or print a symbol. The © line on the copyright page is a courtesy, not a requirement.

What registration does. Registering with the U.S. Copyright Office creates a public record with a date, and it is the ticket to a federal lawsuit if someone copies your book. Register before an infringement, or within three months of publication, and you can claim statutory damages and legal fees. Register late and you can only claim actual losses, which for most books is close to nothing.

What it costs. $45 online for a single work by a single author. $65 for the standard form. Anyone charging you $200 for "copyright registration" is charging $155 for typing.

Do you need it? Legally, no. Practically, for $45, yes if the book has commercial value you might one day need to defend. If you are not sure, do it; it is the cheapest insurance in publishing.

The "poor man's copyright". Mailing yourself a sealed copy proves nothing in court and never has. If you see a service recommending it, close the tab.

A note for authors in Spain

• ISBN: Agencia del ISBN, €45 per edition. You can register as an author-publisher without creating a company.
• Depósito legal: this is Spain's equivalent of the Library of Congress copy, except it is mandatory for printed books distributed in Spain and the responsibility is the printer's. It is free. If you print on demand through Amazon or Ingram, you are not distributing from Spain, and no depósito legal is generated; that is normal.
• Registro de la Propiedad Intelectual: optional, like U.S. registration, around €14-20 at your regional office. Useful for the same reason: a dated public record.
• If you publish in both markets under a U.S. imprint, as we do, the U.S. rules apply to the registration and the Spanish ones to anything physically printed and sold in Spain.

What goes on the copyright page, then

Title, author, publisher name and city, edition and year, "© 2026 Author Name. All rights reserved" (or the Spanish "Todos los derechos reservados"), the ISBN of this edition, the LCCN if you have one, and a credit line for the cover and the typesetting. That is the whole page. Everything else people put there is decoration.

Checked 3 October 2026 against Bowker, the Agencia del ISBN, the U.S. Copyright Office fee schedule and the Library of Congress PCN program guide.