presenting PDF files

Hi

I have a program that comprises of 20 plus 'books' which are PDF files that I need to add to my site as members only content. What would be the best way of doing this? 

You can use the files module to upload and have access to the files.  As for display, there use to be a couple of modules in the market for this.  The modules used a pdf viewer that was third party and those third party viewers may no longer be working.  You can search the market to see if there are current modules for pdf files.