Once you created a PastBook, it stays with you forever! Log in with PastBook and find yourself on the page with the book which you created last. Press the “Menu” button on the upper left corner, pick and check the list of the books that you have created. You can always come back to a certain book and edit it.
Using the app, you can work on one book at a time. If you press the “Back” button, you will no longer have access to this book from your phone, unless you have bought it or shared it on Facebook or Twitter. In this case, you can access the book from the web, just sign into your account.