Using WinCounter as a people counter at the entrance to your library can give
you a valuable insight into the times and volumes of people arriving and
leaving.

By mounting two sensors in the appropriate configuration, the Professional Edition of WinCounter can be setup to show the direction of the people entering or exiting the library.
If you have directional sensors then you can have WinCounter display an on-screen total which lets you see the total head-count of people in the library at any time. This is based on the difference between the counts from entry and exit sensors.