To remove a saved book, navigate to the “Home” section. Tap “My Books” to get to a full list of your saved books. Press "Edit" and choose the book you would like to remove.
You can also remove a book directly from your home screen. Either by clicking the book and then tapping “X - Saved” on the left below the cover, or by long pressing the cover anywhere in the app and tapping "Remove from My Books" from the book menu that pops up.
If you remove a book from "My Books" that you have downloaded, you will receive a warning that the download will also be removed. You can cancel the removal at this point if you want.