The navigation bar in iBooks is exactly what I'm looking to implement. That is, a transparent top bar with the return button in the top left and some buttons in the top right to invoke actions.

However, I'm not exactly sure how this effect would be accomplished. The transparency especially. Can anyone point me in the right direction of how I might accomplish this?

![enter image description here](https://i.stack.imgur.com/EbFh0.jpg)