First and foremost, I am aware of the existence of this question - How do I add a library project to Android Studio? - and unfortunately, it has not helped me.
My go
dependencies { compile 'com.google.guava:guava:19.0' }
Source: https://github.com/google/guava
EDIT: As of v22, there's specific guava version for Android.
dependencies { compile 'com.google.guava:guava:22.0-android' }
* Thanks Sam :)