booklibs.engineer is a PDF search engine and do not store, hold or retain any files. The original creator or rights holder owns the files. We merely displays links of files available freely on the web.
booklibs.engineer has not copied or published your files, the files that appear through booklibs.engineer are being loaded from your server where you have published the files and made them publicly available.
booklibs.engineer searches the web and displays details of PDF files that are freely and publicly available on the internet. If you do not want search engines to index your PDF files (or other specific filetypes) you can use an X-Robots tag within your HTTP header to prevent this. Here is a Google page about the topic: http://code.google.com/web/controlcrawlindex/docs/robots_meta_tag.html
We're not infringing your rights, we haven't copied your files and we're not doing anything wrong. If you really need us to remove a file whilst you sort out your server or get a file removed from our site then we encourage you to contact us via Contact page