The second most popular web browser, after Google Chrome (21% market share as of June 2015), which is quite impressive for an open-source project born from the battered corpse of Netscape after it was defeated by Internet Explorer, then stripped and eaten by AOL. After almost two years since its initial 0.1 release, Mozilla Firefox, or just Firefox, launched version 1.0 on November 9, 2004. Versions 2, 3, and 4 came out in 2006, 2008, and 2011, after which they changed the criteria for being a new version and they started to roll out faster. As of November 2017, 57.0 is the official released version for desktops.

Firefox started its life in September 2002 as an experimental branch of the original Mozilla Suite (since discontinued in favor of the community-maintained [[SpiritualSuccessor SeaMonkey]]) called Phoenix. The Phoenix name ran into trademark issues with Phoenix Technologies, so it was discontinued in favor of Firebird. That name, in turn, was criticized by the developers of the free/open-source Firebird database server, even after Mozilla [[InsistentTerminology insisted]] their browser be called ''Mozilla'' Firebird, thus necessitating a second name change. Regardless of what you call it, the browser is mostly known for being hugely and relatively easily customizable through the use of add-ons and scripts, something it inherited from the Mozilla Suite.

For more detailed information, see its [[http://en.wikipedia.org/wiki/Mozilla_Firefox page]] on Wiki/TheOtherWiki. The browser's official webpage can be found [[https://www.mozilla.org/en-US/firefox/new/ here]]. In addition to the desktop version, Mozilla has also released a mobile version for the Android operating system, which can be downloaded from the Google Play store.

You don't actually have to be able to think in Russian to use it, though you might think so if you confuse the browser with [[Film/{{Firefox}} the 1977 novel or its 1982 Clint Eastwood film adaptation]].