The Portable Document Format (PDF) is a popular format to publish formatted text and documents. There are several different versions of it, some qualifying as an Open Standard, some certified by ISO and some encumbered by software patents. You might want to promote the versions that are Open Standards, because Open Standards guarantee interoperability, competition and choice. Read more… There are many programs to read and write PDF documents. All of the PDF readers in the following list are Free Software, respecting your basic four freedoms to use, study, share and improve them. This gives you control over your computer and helps protect your privacy. Read Read more