GUIDED BY JUDAISM'S REVERENTIAL regard for — and fidelity to — the dignity of the written word, many Jewish communities, right up to the present day, keep a geniza, or repository for discarded sacred texts to gather dust or disintegrate. Such repositories, often in synagogue attics or cellars, hold anything bearing the name of God, texts with scribal errors or physical damage, or sometimes anything written in Hebrew characters. 

These storerooms have functioned both to protect a text's sanctity and to hide away heretical texts. Concealing both the sacred and the censored, the geniza, as one scholar put it, serves "the twofold purpose of preserving good things from harm and bad things from harming." Whether for the purposes of preservation or banishment, a geniza offers a dignified way of consigning a text to oblivion.

But as the essayist Adina Hoffman and the poet and translator Peter Cole make clear in Sacred Trash, for antiquity and sheer wealth of forgotten treasure, none compared with the geniza of Cairo's Ben Ezra synagogue (first built in the eighth or ninth century), which had accumulated the largest collection of medieval manuscripts in the world. Their book offers an elegant history of one of the great modern feats of cultural resurrection: the rediscovery of the Cairo geniza, which served as what Hoffman and Cole call "an inadvertent archive" for almost 10 centuries. 

¤

In May 1896, on returning from a trip to Cairo, Agnes Lewis and Margaret Gibson — Scottish twin sisters and self-taught maverick scholars — brought home to Cambridge a few Hebrew fragments and showed them to their eccentric friend Solomon Schechter, Cambridge's reader in rabbinics. Much to his astonishment, the savant recognized one stained leaf as belonging to the Hebrew original of the apocryphal, epigrammatic second-century BCE book of Ben Sira (later known by its Latin name, Ecclesiasticus). The work had been known only from its Greek and Syriac translations; no copy of the Hebrew original had been seen for almost a thousand years. 

In fevered excitement, Schechter set off to Cairo on a secret mission to the source of the remarkable manuscript. Aided by his charismatic force of personality, and not a little baksheesh, he was at last admitted into the synagogue's geniza. Undaunted by legends that the place was protected from prying eyes by curses or scorpions or poisonous vipers, he clambered up a ladder and crawled through a hole in the women's gallery and into a room haphazardly filled with moldering manuscripts undisturbed for generations. "It is a battlefield of books," he said of the vertigo he felt at that moment,

and the literary production of many centuries had their share in the battle, and theirdisjecta membra are now strewn over its area. Some of the belligerents have perished outright, and are literally ground to dust in the terrible struggle for space, whilst others, as if overtaken by a general crush, are squeezed into bi...