it’s possible for you to load them from your Google Drive account or from your setup.

Open Google Play, selectMy Books, and sign in to your Google account if asked.

SelectUpload filesto browse for the e-book.

My books on Google Play Books screenshot

To upload a book from your setup, go to theUploadtab.

Otherwise, look underMy Driveto choose an e-book from your Google Drive account.

ChooseSelectwhen you’ve chosen all the books you want to upload.

Upload files button on Google Play Books screenshot

Your items may take a few minutes to have cover art appear.

Another missing feature is the ability to meaningfully organize these books with tags, folders, or collections.

It was a closed system, and you could only read books purchased from Google.

Google Books upload screen with the Select button highlighted

The most requested feature for Google Books was some sort of cloud-based storage option for personal libraries.

you’re free to still do that, but it has some disadvantages.

If you use a local e-book reader app like Aldiko, your books are also local.

If you lost your phone without backing up those books somewhere else, you also lost the book.

It doesn’t match the realities of today’s e-book market to keep e-books offline.