Although PDF still is closely associated with Adobe's Acrobat family of tools, you don't always need Acrobat to do useful work. And even though many of the hacks are specific to particular commercial tools (Acrobat 5, Acrobat 6 Standard, or Acrobat 6 Professional) or are bound to a particular operating system, overall the book tries to stay as environment-agnostic as possible. Whether you're running Windows, Mac OS X, or Linux, there should be a way to do most of the things described here. Some hacks are specific to a particular operating system, in which case they will say so.