When you select a page and start looking at content or adding information, the notebook panes slide off to the left to leave more space on screen for your notes.

Tap on the notebook name to get them back on screen, or open both the notebook lists and see other handy commands like forcing a notebook to sync or copying a link to your notebook by swiping up from the bottom of the screen to open the App Bar.

That's a standard Windows 8 gesture – if you don't have a touch screen, it's right click on a mouse, but Microsoft is keen to push OneNote for Windows 8 as a touch app.