I recently made a Mac Automator Workflow that allows you to easily stitch together multiple PDFs into a single document. The workflow creates a new PDF while also To use the workflow on your own computer:

  1. Download the .zip file and extract the workflow from the archive.
  2. When OSX prompts you with "Do you want to install the “Combine PDF Files” service?", click "Install".
  3. Navigate to the directory in which the PDFs you wish to combine can be found. Select all of the files at once, and right-click the selection. At the bottom of the menu, click the option called "Combine PDF Files".
  4. The workflow will ask you to name the new file (including its extension) and to choose its location. Voila!