android develop – Guides
http://developer.android.com/guide/
android develop – API Reference
http://developer.android.com/reference/
android develop – Tools
http://developer.android.com/tools/
android develop – Training
http://developer.android.com/training/
android develop – Google services
http://developer.android.com/google/
android Design
http://developer.android.com/design/
android Distribute