On our website
Click on the title you wish to save to your bookshelf and then again on the button Save beneath the cover of the book.
To remove the title, click again on the Save button. If you have removed it, it will no longer be grey.
In the app
The book will be added to your bookshelf automatically if you click on Play book/Read book. You can also click on the heart icon in the bottom left corner of the cover to save the title to your bookshelf.
To remove the title, go to your bookshelf and click on the tool bubble with 3 dots in it next to the title. Click again on Remove from bookshelf.
Keep in mind: You can't remove a title that you've listened/read most recently and that's still in the Player. Listen or read to another title first, and then try again to remove the first title.