Bookshelf and books have disappeared !

[hockeybuff]

After downloading a new version of a previously installed app, I notice now that my iBook bookcase has disappeared. Yet, when connected to the PC, under Device name the BOOKS folder shows most of the books -- just not the most recent ones. How can I restore the iBook Bookcase plus books? Thanks.

 

[hockeybuff]

I should have mentioned (above) that none of the books were obtained thru the iTunes Store. They were simply downloaded (from the internet) onto the PC and then transferred to the iPad. Therefore it is my understanding that syncing would simply clean everything else off the iPad including the listing of Books that appear in iTunes MY DEVICE when connected to the PC. Thanks.