Apple released iTunes 11.1.3 on Tuesday. The maintenance release fixes a problem with the equalizer and, "improves performance when switching views in large iTunes libraries."
Apple's patch notes:
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.
iTunes 11.1.3 is available now in the Mac App Store under Mavericks as a 230MB download.