It could be that you only have interest in iOS or Android. You should be able to easily skip to the sections you're interested in unless you're intrigued about how the other half works! If, like me, you're a capitalist, then you should be interested in both the operating systems.

Far fewer steps are needed to get the Android SDK than the iOS developer tools because for iOS, we have to sign up as a developer with Apple. However, the configuration for Android is more involved. We'll go through all the steps for Android and then the ones for iOS. If you're an iOS-only kind of person, skip the next few pages and start up again at the Becoming an iOS Developer section.