What are Previous iTunes Libraries?

Previous iTunes Libraries
Originally uploaded by Joseph Palumbo.

I've always been irritated by the Previous iTunes Libriaries folder. What is it? What purpose does it serve? Can I delete without crashing my system? Of course I can, Mac oS X is Unix.

According to Article 301895 in the Apple knowledge base, this folder is created any time you upgrade to a newer version of iTunes and can be used to restore your music library if it does not appear in the newer version.

However, if your like some people and have such an intense confidence in all of Apple's upgrades, than feel free to give it the short drag to the trash bin.