In August, I announced The Shelf, which allows you to import, via drop or copy, many kinds of data into it to hold until it is needed later. Check out the original article for full details and a demonstration of The Shelf.
It is now available to download on App Store.
During beta testing, I received many requests for PDF support, I was able to add this in time for release.
During App Review, I was told by Apple repeatedly that The Shelf was an unacceptable app type for Auto-Renewing Subscriptions. As a result, I have changed the business model from yearly subscriptions to a one-time IAP to unlock unlimited items in the App. I hope that this will cover the cost of all further development and as a result I will not need to charge for anything else in the future, but I cannot guarantee that at this stage.