Overall, it is a great app. But one big issue I have is when I'm trying to go through the spells in the books. Example: PHB, Wizard Spells - takes you to a page listing all cantrips and spells (great), choose a spell, and it will sometimes take you to the spell description or not. Try and go back to the list, and it closes the book. You have to return to the index feature and scroll back to wizard spells, which puts you back at the top of the page list. If this were fixed, 4/5 rating.