Generally satisfied with the app. The library contains a majority of books from Thieme publication; reading them is quite smooth, searching for specific terms and keywords is much easier than going back and forth between the index and the chapters within a print version. You can highlight sentences, add your own notes and look up some terms you might not be familiar with. However I am taking away two stars because the app gets laggy and crashes sometimes, specially while rotating the device and changing the orientation of the page, or jumping to chapters. Also you would expect better support for Apple Pencil like annotating and marking up on the pages.