A neat little post on MetaFilter on the history of alphabetization. We take it for granted, but someone had to develop the system (and I am sure someone else was there to say “what’s wrong with the way we do it now?”).
Buried somewhat within the comments (which on many MetaFilter posts can be more interesting than the posts themselves) was a link to the Straight Dope’s background on the Dewey Decimal System.
(warning: MetaFilter can be a not-safe-for-work place; there is no telling what types of topics will be posted)