This document outlines the history and key details of the Android mobile operating system including its version history from Gingerbread to Lollipop, estimated revenue figures, Google's acquisition of Android in 2005, the founding of the Open Handset Alliance in 2007, and the launch of the T-Mobile G1 phone and Google Nexus series. It also briefly discusses Android's Material Design, lock screen changes, widgets, competitors within the Android ecosystem, its competition with iOS, and Android's current market share which is over 76% globally.