The Firefox project began as an experimental branch of the Mozilla project by Dave Hyatt, Joe Hewitt and Blake Ross. They believed the commercial requirements of Netscape's sponsorship and developer-driven feature creep compromised the utility of the Mozilla browser. To combat what they saw as the Mozilla Suite's software bloat, they created a stand-alone browser, with which they intended to replace the Mozilla Suite. On April 3, 2003, the Mozilla Organization announced that they planned to change their focus from the Mozilla Suite to Firefox and Thunderbird.

The Firefox project has undergone several name changes. Originally titled Phoenix, it was renamed because of trademark issues with Phoenix Technologies. The replacement name, Firebird, provoked an intense response from the Firebird free database software project. In response, the Mozilla Foundation stated that the browser should always bear the name Mozilla Firebird to avoid confusion with the database software. Continuing pressure from the database server's development community forced another change; on February 9, 2004, Mozilla Firebird became Mozilla Firefox, often referred to as simply Firefox. Mozilla prefers that Firefox be abbreviated as Fx or fx, though it is often abbreviated as FF. The Firefox project went through many versions before 1.0 was released on November 9, 2004. After a series of stability and security fixes, the Mozilla Foundation released its first major update, Firefox version 1.5, on November 29, 2005. Mozilla Firefox 1.5.0.12 is the final version officially supported under Windows 95.

On October 24, 2006, Mozilla released Firefox 2. This version includes updates to the tabbed browsing environment; the extensions manager; the GUI (Graphical User Interface); and the find, search and software update engines; a new session restore feature; inline spell checking; and an anti-phishing feature which was implemented by Google as an extension, and later merged into the program itself. In December 2007, Firefox Live Chat was launched. It allows users to ask volunteers questions through a system powered by Jive Software, with guaranteed hours of operation and the possibility of help after hours. Mozilla Firefox 2.0.0.20 is the final version officially supported under Windows NT 4.0, Windows 98, and Windows ME.

Mozilla Firefox 3 was released on June 17, 2008, by the Mozilla Corporation. Firefox 3 uses version 1.9 of the Mozilla Gecko layout engine for displaying web pages. This version fixes many bugs, improves standard compliance, and implements new web APIs. Other new features include a redesigned download manager, a new "Places" system for storing bookmarks and history, and separate themes for different operating systems. The latest version under 3.0 is Firefox 3.0.19.

Development stretches back to the first Firefox 3 beta (under the codename 'Gran Paradiso' which had been released several months earlier on 19 November 2007,and was followed by several more beta releases in spring 2008 culminating in the June release. Firefox 3 had more than 8 million unique downloads the day it was released, setting a Guinness World Record.

source : wikipedia.org