The mid-20th Century discovery of hundreds of manuscripts of the Hebrew Bible as well as previously unknown texts from the Second Temple Period transformed the understanding of the formation of the texts of the Hebrew Bible and the nature of Judaism in that period. These manscripts are known collectively as the "Dead Sea Scrolls" (= DSS).
Previously, the oldest texts of the Tanakh in Hebrew had been the great codices (e.g., the Aleppo Codex) which dated to roughly 1000 AD/CE. Even though Greek manuscripts of the septuagint came from earlier centuries, the Hebrew form of the text was poorly represented.
The full impact of this discovery took decades to be realized, as these manuscripts -- many in a very poor state of preservation, and broken into thousands of fragments -- were studied by a restricted group of elite scholars. This situation changed in the early 1990s in a period charged with controversy, when the DSS finally became available to the study of any interested scholar.
Just over one-fifth of the manuscripts found are biblical, with the rest belonging to a variety of genres (hymns, commentaries, handbooks, etc.) illustrative of a strand of Judaism in the period often linked to the Essenes, although this identification is still contested.
- The Orion Center for the Study of the Dead Sea Scrolls at the Hebrew University in Jerusalem
- The Leon Levy Digital Dead Sea Scrolls Library, a partnership between the Israeli Museum and the Google Cultural Institute
- Wikipedia on the DSS
- Library of Congress online exhibit (dated, but still worthwhile)
- The West Semitic Research Project's Educational Site: Dead Sea Scrolls