If you have a Macintosh running OS X, the operating system includes a Preview application that enables you to look at PDFs without downloading Acrobat Reader.
Apple's latest operating system, Mac OS X, uses PDF all over. Icons and other pieces of applications are PDFs, the rendering system is tied closely to the data model used by PDFs, and any application that can print can also produce PDFs. Given this fondness for PDF, it makes sense that the Preview application Apple provides for examining the contents many different file types also supports PDF.
The Preview application is installed on Macs at Macintosh HD:Applications:Preview. It reads a variety of graphics formats, including JPEG, TIFF, and GIF, as well as (of course) PDF. You can open PDFs in Preview by selecting File Open . . . , by dragging their icons to the Preview application, or (if Acrobat isn't installed) by double-clicking. An open PDF in Preview looks like Figure 1-3.
Preview's overall interface is much simpler than the Acrobat Reader's interface, though the options are friendly and clear. Preview also creates thumbnail images of pages, which is convenient for quick navigation. Preview also supports the PDF-creation functionality built into Mac OS X [Hack #40] .
Also, Preview's File Export . . . command enables you to save the PDFs or graphics you're examining in any of a variety of PDF formats. If you need to convert a JPEG to a PDF file, or a PDF to a TIFF file, it's a convenient option. (It's also worth noting that screenshots taken using Mac OS X's Command-Shift-3 or Command-Shift-4 options are saved to the desktop as PDFs. Those PDFs contain bitmaps, much as if they were created as TIFFs and exported to PDF through Preview.)