In order to contribute to building applications on Android whether it from a product owner perspective or a developer perspective or someone that just wants to build an Android app for his/her own business, it is important to know about Android. There are many misconceptions such as, Android is a front end just like web, Android is a hardware phone etc. Of course it can be used as a front end and there are many hardware phones that are powered by Android but Android is just an operating system like windows that is built for running on smaller computers and phones. Android can also be used as servers as such although it might not be best suited for it. It is an open source operating system based on Linux kernel. The reason Android is popular is because multiple hardware manufacturers and consumers can install the operating system for free but there might be other things can be acquired via license.