Inside a book, tap screen to show menu, and then follow the steps below:
1. Tap the export/share button
2. From the popup menu, select Book & Notes
3. A list of export options show up. Select your choice, such as AirDrop email, or a cloud storage (google, microsoft, amazon, apple) and follow directions.
You can export an entire book in HTML format to any device via AirDrop, email, or any other means. If the receiving device also has Gutenberg (or Librivox) App installed, it will open the received book directly on the same page it is exported. You can thus send a book you are reading between your own devices without having to search for your last reading page.