A: ZIP files are archives containing one or more files in a compressed format. ZIP files are used to save space and to conveniently group sets of files into a single downloadable file.

Most modern operating systems feature built-in support for ZIP archives (sometimes referred to as "Compressed Folders").

In order to extract the files contained in a ZIP archive you can use an "unzip" tool or a more sophisticated ZIP front-end (which usually can both read and write ZIP files). If you are not satisfied with the built-in operating system support, We recommend the following packages, which also come in partially free versions.

The following programs are free:

• 7-Zip (our favorite, for Windows, macOS, GNU/Linux and other platforms)
• StuffIt Expander (Windows, macOS)
• WiZ (Windows)
• MacZIP (macOS)

The following packages are commercial, but include a free evaluation version:

• WinRAR (Windows, macOS, GNU/Linux and other platforms)
• WinZip (Windows)
• PKZIP (Windows, GNU/Linux and other platforms)
• StuffIt (Windows, macOS)

For additional information on the ZIP file format and free software you may want to visit Info-ZIP.