The creatively named “Sensuella” needs to be brought up to date. Specifically:
I have lots of books segmented into small MP3 parts so I have tons of files listed in iTunes main library. Does iTunes support folders in the main library? It takes a long time to scroll long columns.
If you mean the area of the iTunes window that displays tracks, the answer is no. There are ways around this, however. For example, you could invoke iTunes’ browser view (Command-B). Click the Audiobooks entry in the first column and you’ll see just those entries whose genre is Audiobooks (and if they don’t have that entry, you should assign it to them in each track’s Info window or select all your audiobooks, press Command-I, and change the genre in the Multiple Song Information window).
If that view contains too many tracks for your taste, create a smart playlist for each book—one that reads Name is War and Peace, for example. This gathers all segments of each audio book into a separate playlist. In iTunes 5 you can then create a new folder, call it My Books, and move all these smart playlists into that folder.