How to recreate libraries in iTunes
You can add your files to your iTunes library without having iTunes copy the files to its own folder. Go to iTunes &gt; Preferences &gt; Advanced and un-check Copy files to iTunes Media folder when adding to Library. This will let you drag-and-drop entire folders into iTunes, and it will add them to its iTunes Library xml file without making copies of all of your files. 

(If you keep that checked and un-check the other option on that preference pane, Keep iTunes Media folder organized, iTunes will copy all of the files you drag into it, but it will preserve the naming and file structure of the original source folder.)