This version of iTunes resolves an issue where the equalizer may not work as expected and improves performance when switching views in large iTunes libraries. This update also includes additional minor bug fixes.
Note: If you are using OS X Mavericks, your book library can now be found in iBooks for Mac.
For information on the security content of this update, please visit: support.apple.com/kb/HT1222.
Users can download the iTunes 11.1.3 update via Software Update on their Macs.