kashf aDH-Dhunun has listed more than 80 arbayins. this week i found a book in the sharjah book exhibition titled al-mu`yin ala ma`arifati kutub al-arba`yin by sahl al-`ud. in this book he lists 529 books titled arba`yin in aqidah, fiqh, tasawwuf, etc all listed alphabetically. interesting addition to any bibliophile's library.