Currently Being ModeratedJul 16, 2012 8:36 PM (in response to Ariantg)
is this second library in a different account on the computer?
Look at Home Sharing.
iTunes: How to share music and video - http://support.apple.com/kb/HT2688 - about Music Sharing and Home Sharing
Home Sharing Support page - http://www.apple.com/support/homesharing/
iTunes: Setting up Home Sharing on your computer - http://support.apple.com/kb/HT4620
iTunes Home Sharing now works between users on same computer - https://discussions.apple.com/thread/3865597