The Technology is increasing day by day and many innovations are coming into existence the main intention of the documentation of secret of smart phones is to make the people aware about the working system of presentation mobile operating systems of smart phones that is android mobile operating system. The documentation contains the detailed explanation of platform, software development, features, building blocks of an android mobile operating system. It also contains the detailed explanation of fro yo,ginger bread and honey comb versions of android. The Android platform which has developed by Google is going to play major role in Mobile applications because as it is an open source and it is also easy to develop mobile applications using Android as because in order to develop these applications all the APIs are available and these APIs are as same as java APIs which are easy to understand. We can only hope that the next versions of Android have overcome the actual limitations and that the future possibilities became a reality.