If the works are copyright, then it is an infringement. Please don't post any links to copyright materials or offer to send them to people. Forums are responsible for copyright abuses posted on them.
If you wish to quote a short passage from a book in order to ask a question about what has been said, that's fine. Don't forget to acknowledge your source.
If your plan was to post a link to the whole book in pdf form, I would suggest that you not do so. Unless you got the books from a clearly free source where it states "Copyright-free. You are free to download and share this material without restriction", then I don't think it's a good idea. Where did you get the pdfs from originally?
I freely downloaded them from other English learning sites some time ago, but most download links no longer exist now.
Just forget it as you don't think it's a good idea.