* Format: The most obvious difference might be the physical format. One could be a paperback, the other a hardcover; one a mass-market paperback, the other a trade paperback; one an ebook, the other a print book.
* Content: While rare for major differences in a true "edition," there might be minor textual alterations. This could include corrections of errors, updated information (especially in non-fiction), or even slightly different introductions or afterwords.
* Illustrations: The illustrations could be different, perhaps due to updated artwork, or the inclusion/exclusion of certain images.
* Publisher: Sometimes, a book's rights are sold to different publishers, leading to different editions with differing cover art, interior design, and even minor text changes.
* Language: An edition might be translated into another language.
* Cover art: The most visually apparent difference is often the cover art. Even with the same content, publishers frequently update or change cover art for new editions or to appeal to different markets.
* Print Quality/Binding: The paper quality, binding, and overall production values can vary significantly, leading to differences in price and longevity.
* Publication Date: Each edition will have its own publication date.
In short, while they may share the same basic story or information, books with different ISBNs, even if sharing the title and author, are considered distinct publications due to at least one of the above variations.