Rapaire notes:

A good compouter system will have a way to cross-check bad spelling.

A common check is the "sounds like" search. When the few indexes with this feature first appeared, they made it sound like they had something really special; but it usually is accomplished simply by deleting all the vowels in the search string the user puts in. You need a crosslinked "unvowelled" list to search, and it's almost mandatory that the system be able to display multiple returns so the user can narrow it down. Unfortunately, users can still enter gypographic erros, and will still blame the librarian when they can't find what they want.

John