Today on the New Yorker Page-Turner blog, Emily Greenhouse has an interesting (and thorough) piece about the Cairo Geniza.
To this day, synagogues collect expired prayer books and ritual objects, and bury the contents every few years. Historians were doubly lucky with the worshippers at Ben Ezra, who not only deposited written texts into the genizah, but, for some reason, never buried its contents. (Instead, they stored it in what was literally a hole in the wall). As a result, we have a frozen postbox of some two hundred and fifty thousand fragments composing an unparalleled archive of life in Egypt from the ninth to the nineteenth centuries. The community may have been somewhat atypical—many of its Jews were wealthy, living at the center of a mercantile network, and Fostat was safer for Jews than the Land of Israel. Still, scholars can extrapolate a great amount of information from the Genizah documents about life for Jews during the Islamic Period in cities such as Baghdad, Damascus, and Aleppo. No other record as long or as full exists.
The Cairo Geniza has long been a fascination of the historians and Jews alike and Nextbook Press even put out a critically acclaimed book called Sacred Trash written by Adina Hoffman and Peter Cole about its contents.
They also spoke about their book and their work for Vox Tablet, which made for a fantastic podcast. Check it out here.