Sumatra PDF is a slim, free, open-source PDF viewer for Windows.
Sumatra PDF是一款小巧、免費、開源的PDF閱讀器，只有一個文件。

Latest Changes:

• Added ability to select the text and copy to clipboard
• Made it multi-lingual (13 translations contributed by many people)
• Added Save As option
• List of recently opened files is updated immediately
• Fixed .pdf extension registration on Vista
• Added ability to compile as DLL and C# sample application
• Mingw compilation fixes and project files for CodeBlocks
• Fixed a few crashes
• Moved the sources to Google Code project hosting

Download: Sumatra PDF 0.7