This is the book:
The Lost and Found World of the Cairo Geniza by Adina Hoffman, Peter Cole
This is what it is about:
Hoffman and Cole’s vivid portrayal of the discovery of the ancient Cairo Geniza — the world’s richest depository of Jewish manuscript fragments, which the authors playfully describe as “a kind of holy junk heap’’ — is equal parts treasure hunt for the sacred and historical and Herculean rescue of important texts.
The exploration of the geniza was sparked by Agnes Lewis and Margaret Gibson, identical twins who lived in Cambridge, England, and were scholars of Arabic and Syriac, a dialect of ancient Aramaic. The sisters, originally from Scotland and the daughters of a Presbyterian minister, were well acquainted with the Hebrew of the Old Testament. But some of the fragments the sisters brought back from their travels in the Middle East appeared to be outside of the Biblical canon. In May 1896 they invited their friend and colleague Solomon Schechter to tea to identify the passages. The decision to involve Schechter — who would eventually become chancellor of the Jewish Theological Seminary of America and have his name memorialized through the network of Conservative Jewish day schools — would prove fateful.