PDFTK Builder is a small tool that lets you make certain changes to PDF
documents. In particular, PDFTK Builder allows to combine several PDFs
into one and indicate the page ranges to be included from each.
It's also possible to restrict the edits that other users can make to
the file. If you want to prevent your content from being copied, you can
untick the corresponding box. You can do the same to prevent users from
printing, adding information, making changes, etc. It's also possible
to restrict who can open the document by adding a password.
Other operations you can complete with PDFTK Builder include: saving
each page of the PDF separately, adding a watermark from another PDF
file, or rotating selected pages. 
PDFTK Builder is a free graphical interface to the Windows version of PDFTK making it much easier to use.