Adobe Acrobat is expensive, but that doesn’t mean you have to live a life without portable documents. What many people don’t realize is that PDF is a Federal Information Processing Standard, which means the specifications behind the format are widely published.

Open source products comprise the work of many collaborators -- sometimes thousands of them, and often separated by oceans. Each person works on small portions of a project, and anyone is welcome to contribute. The finished product will be available freely for anyone to download and, in most cases, modify.