Nowadays, as the developing of hardware for cellular phones is becoming much better, the performance index is significantly higher than the legitimate specifications of the software configuration. Features of Mobile phone's depends completely on software. As the Android operating system is getting considerably prominent, the application based around Android SDK appeals to much more attention. Because of technological advancement, mobile terminals have actually evolved into functionally sophisticated devices such as, for instance smart phones and tablets. The Android platform has grown to become one of the most popular operating system alongside millions of new users each and every year. In spite of many studies, no one have presented a comprehensive classification of this particular operating system. In this particular paper we present an impartial review of the Android OS. We summarize the platforms historical past which includes improvements associated with each and every release as well as the systems engineering and project structure. General Terms Google Android Mobile Operating System.