I have mostly ePub books & don't have any problems. There is a lot of support for the format & Calibre is a good tool for converting files. I am currently using the free Aldiko 'cause it was recommended here & it seems to work well. Still learning how to use it & it appears that after the tips screen is cancelled, with imported books (SD card) you must tap the screen for the book to show. I will disable the tips screen & see if that changes. Thought, at first, that it wasn't working on imported books. Edit: OK the blank screen thing went away???? The books reside on the SD card, so it must remain in tact as far as I know. It would be nice if they could be stored in internal mem.Cheers,kev