Can't Get UI buttons to work.

I've Added a Canvas. Then added a Rect Transform as a Child With a Raw Image component. Then added a button as a child of the Rect Transform. However I can't get the button to do anything.

here is a Screenshot of my Hierarchy and my Canvas in the inspector

And a Pic of my Button in the inspector

The Button's Image shows fine, however it doesn't highlight on mouse over and it doesn't run the click event when I click it. Can't figure out what I'm doing wrong.

Please help. Thanks