From the settings, you can choose which books you want to pull quotes from or even add your own. You can also set a timer to regulate how often the quotes pop up, or you can set it up with a hotkey.
You can establish a maximum size for the windows and the exact location in which you want them to appear.
PopUp Wisdom is a fun program. It's not the most useful thing in the world, but it will make you smile, and that's worth something.