Combining PDF files on a Mac

Sometimes we have to combine various PDF files, such as a title page and a score or movements of a piece, into one document. If you are on a PC, I'm afraid you'll have to shell out some bucks to get software that does that. Acrobat Pro works quite well. However, Mac's Preview does this quite easily.

1. First, open your documents in Preview.  
2. If Preview is your default PDF reader, then your documents will open in it when you click on them.  Otherwise, ctrl-click on your document and select Open with > Preview.
3. In the upper left-hand corner of the Preview window you will see a drop-down box.  Click on that and select "Thumbnails" in both documents. 
4. Resize your windows so that they are side-by-side.  You can do this by placing your cursor over the edge of the document until it appears as a double-sided arrow. Then ctrl-click and drag in the direction that you need in order to make the window fit properly.
5. Go to the window of the document that you want to be first and click on the top thumbnail if it isn't already selected. Then you can either type cmd-a, or go to the Edit window and choose "Select All". You should see a shadow box around all of the thumbnails for that document. 
6. Next, click and drag those thumbnails and place them above the first page of the other document.  If there are several pages, be patient because it takes a couple of seconds to process the drag and drop.

Now you have your combined document!