Close Library tool

I accidentally closed my Library tool. I hit the little arrow in the top right corner and now I have a blank area where my library used to be! how the hell do I get it back again? I can't do anything and I've looked but can't see anywhere that will bring it back again.
Please if anyone can help.......


Not to worry, I have it sorted now. You right click on the balnk area and a drop down menu appears.