Have you ever wanted to take several one-page PDF documents and merge them into one multiple-page PDF document? Mac OSX (Leopard and Snow Leopard) makes it easy! To join two or more pdf files together, open the pdf file in preview, open the thumbnail view (Shift-⌘-D), and drag a second pdf file ON TOP OF an existing page thumbnail. The two documents will merge into one! Then, simply save the new combined file and you're ready to go!