Accessing Files Outside the Web Root

Let me preface my question by noting that I am virtually a PHP novice. Although I am a long-time webmaster, and have used PHP for some years to give visitors access to information in my SQL database, this is my first attempt to use it for another purpose. I have browsed the mailing list archives and have searched online but have not yet succeeded in teaching myself how to do what I want to do. This need not provoke a lengthy discussion or involve extensive hand-holding - if someone can point to an appropriate code sample or online tutorial that might do the trick. I am the author of a number of PDF files that serve as genealogical reference works. My problem is that there are a number of sites which are posing as search engines and which display my PDF files in their entirety on their own sites. These pirate sites are not simply opening a window that displays my files as they appear on my site. They are using Google Docs to display copies of my files that are cached or stored elsewhere online. The proof of that is that I can modify one of my files and upload it to my site. The file, as seen on my site, immediately displays the modification. The same file, as displayed on the pirate sites, is unmodified and may remain unmodified for weeks. It is obvious that my files, which are stored under public_html, are being spidered and then stored or cached. This displeases me greatly. I want my files, some of which have cost an enormous amount of work over many years, to be available only on my site. Legitimate search engines, such as Google, may display a snippet, but they do not display the entire file - they link to my site so the visitor can get the file from me. A little study has indicated to me that if I store those files in a folder outside the web root and use PHP to provide access they will not be spidered. Writing a PHP script to provide access to the files in that folder is what I need help with. I have experimented with a number of code samples but have not been able to make things work. Could any of you point to code samples or tutorials that might help me? Remember that, aside from the code I have written to handle my SQL database I am a PHP novice. Dale H. Cook, Member, NEHGS and MA Society of Mayflower Descendants; Plymouth Co. MA Coordinator for the USGenWeb Project Administrator of http://plymouthcolony.net