THE ANXIOUS BENCH: Alternative Scriptures: The First Discovery of Qumran. Philip Jenkins reviews the discovery of the Cairo Geniza in the late 19th century. Solomon Schechter found portions of the Damascus Document in the Geniza. Fragments of the Damascus Document were found much later among the Dead Sea Scrolls and it turned out that it was a Qumran sectarian document.
Schechter drew many correct inferences from his medieval copy of the Damascus Document about the Qumran sectarians, although he got some things wrong too.
The first post in Professor Jenkins's Alternative Scriptures series was noted here. Schechter's centennial yahrzeit (death anniversary) was in 2015. See here and here. For past PaleoJudaica posts on the Cairo Geniza, see here and many links.