Public domain Defined.
Definition
A work in the public domain is no longer protected by copyright, usually because its term has run out, so anyone may reprint, adapt or sell it without permission. In the US, works created since 1978 are generally protected for the author's life plus 70 years, so most public-domain books are much older than that.
Sources checked 20 October 2026.
How it works
KDP accepts public-domain books but may ask for proof, and where a free version is already in the Kindle Store it accepts only a differentiated edition: an original translation, original annotations, or ten or more original illustrations, with (Translated), (Annotated) or (Illustrated) in the title field and a short summary of what is original at the top of the description. Public-domain titles are paid at the lower ebook royalty only, can't join KDP Select, and aren't accepted for Expanded Distribution. Copyright terms differ between countries, which KDP reminds publishers of.
An example
KDP's own example: "Pride and Prejudice (Annotated)" is an acceptable title for an edition with original notes on historical context, while "Pride and Prejudice (with an Introduction by...)" is not. The Copyright Office adds that copyright in a new edition covers only the new material: your annotations are yours, and the novel itself stays free for anyone else.
Common mistakes
Assuming every old book is free to copy: a modern translation, introduction or illustrations in an old edition can still be under copyright. Counting a linked table of contents or tidier formatting as differentiation, which KDP says it isn't. And choosing the higher ebook royalty for an undifferentiated public-domain text.
