If it was varnish it would be ronseal One of the first apps I install on every phone and tablet  I don't use the book shelf as I prefer to manage books by folder and open from es file explorer or Dropbox. Love ability to quickly change brightness and page with a swipe  and that I don't have to keep turning device back on if I don't read a page I'm time (as long as 50%+ charge). TL:DR For me it just works the way I want out of box.