You can re-create this book, by editing its pages or changing the page list or the order of the pages, etc.  
When you are finished with this book, however, you should remove its id from the list of book creator pages.  
You do this by clicking on the above button: **Remove page from creator list**.  This will free the page id for other uses. 
Unless you do this, the page will continue to display the **Start** and  **Remove page. .  .** buttons, 
even if you have removed the epub syntax from the page.