Did you know that Apple’s Preview lets you easily annotate and merge PDFs as well as delete and re-order pages within a PDF? Preview is a free application which comes bundled with Mac OS X. Apple has been quietly updating over the years and it has become quite capable and user-friendly. Just a few years ago one would have needed to buy the relatively expensive Adobe Acrobat Standard or Professional PDF Editor to do many of these tasks.

Note: There are slight differences in how certain tasks are done if you’re using OS X 10.5’s version of Preview. All of these demonstrations are done using OS X 10.6’s version of Preview.

It’s also important to know that the following techniques may not work on all PDFs. It’s possible for a person who creates a PDF to lock the file which prevent others from manipulating it. Typically, locking a PDF like this requires use of an application like Adobe’s Acrobat.

I’ve created short video tutorials on how to do the following tasks. Read the brief text description and then click the link to watch the video.

If you need more extensive editing capabilities then what is offered by Preview you should check out the relatively affordable PDFPen.

[Note August 2024:  PDFPen was purchased by a company called Nitro and the application is now named Nitro Pro.]

1. Reorder pages in a PDF – Open a PDF file then click the Sidebar button to view the thumbnail icons for each page. Click on one of the thumbnails and drag the page up or down. Look for the horizontal blue line that appears indicating the new location of the page. To remove a page you can simply click on the thumbnail icon for a page to select it and the press the Delete key on your keyboard.
2. Extract pages from a PDF – Open a PDF file then click the Sidebar button to view the thumbnail icons for each page. Click on the first page you want to extract. If you want to extract additional pages then hold down the Command key and click on additional thumbnail icons. Release the Command key and drag the thumbnail icons to the Desktop. A new PDF file will be created on the Desktop. Rename the file as desired. Open this new file by double-clicking to verify that it contains the pages that you want. You can re-order the pages by following the tip listed above.
3. Move pages between PDFs (Merge PDFs) – Open a PDF file then click the Sidebar button to view the thumbnail icons for each page. Open a second PDF and click its Sidebar button too. Position the two PDFs so you can view both file’s Sidebars at the same time. Select one or more pages from one file’s Sidebar and drag them into the other file’s Sidebar. Look for the horizontal blue line that appears in the receiving file’s Sidebar. This blue line indicates where the new page appear. You can re-order the pages by following the tip listed above. Go to the File menu and select Save to save the changes.
4. Annotate text in a PDF –  Open a PDF file, click the Annotate button to review a row of tools at the bottom of the window. Use these tools to highlight text in a variety of colors, draw a line through the text, enclose text inside a rectangle or oval, or add a note in the margin of the PDF. [Update October 2014: In OS X 10.9, Mavericks, click the “Show Edit Toolbar” button to reveal the row of tools. It looks like a pencil with a box behind it.]

[Update February 2017: In OS X 10.11, the command is “Show Markup Toolbar.”]