Does book you purchase remain on your iPad forever?

Unless you delete it. But then you can download it again from your account.

2315j5132 wrote:

Does a purchase book remain on your iPad forever?

Mostly, yes.

You’ll want to read the legal agreements: Legal - Apple Media Services - Apple

Cases of purchased books disappearing from iCloud are rare. I can’t recall having heard of a case of a disappearing book purchase in recent times.

Details > Redownload books and audiobooks - Apple Support

In general, you’re purchasing a media license, and the license generally remains available and associated with your Apple ID. Your download usually either stays on the device, though some Books-related and storage-related settings can cause the book to be relocated to iCloud and deleted locally, but the purchase can generally be re-downloaded.

This whole area of media “purchase” can be a little murky in the most polite of terms, and can be subject to the various content providers’ licensing and distribution changes, and can also change based on your current country or region:

https://www.slashfilm.com/amazon-sued-purchased-movies/

https://theoutline.com/post/6167/apple-can-delete-the-movies-you-purchased-without-telling-you (read through to the footnote there particularly about the cause of that case, and how those purchases got caught by the purchaser having changed country or region.)