Acrobat Reader is a free but not Free PDF viewer provided by Adobe. There are binaries for many platforms, including Windows and Linux versions.

The PDF page lists a few other viewers, including Free ones.

If you are using RedHat 9 or Fedora, AcrobatReader will probably crash at launch due to a problem with character sets

Warning: charset "UTF-8" not supported, using "ISO8859-1". aborting

This problem occurs if your locale is set to one that uses UTF-8, which many distributions are now defaulting to. On other distributions (such as Debian and Slackware), AcrobatReader prints out the warning but doesn't abort. The locale(1) command will tell you what your locate is set to.

The workaround is to edit /usr/local/Acrobat5/bin/acroread (or wherever the equivalent is located on your system) and add the following lines near the top

LANG=C export LANG

See the UnicodeNotes page if you have no idea what "UTF-8" or "ISO8859-1" means. :-)

Speeding up load times (Reader 6.0 on MicrosoftWindows)

Acrobat Reader loads many plugins when it loads. Removing all unneccessary plugins will mean it loads faster. In the "c:\Program Files\Adobe\Acrobat 6.0\Reader\plug_ins" directory (obviously change this to where Reader is installed), remove all the files except for EWH32.api, printme.api, and search.api.