At Wadi Qumran, about 8 kms south of Jerusalem and 2 kms from the north-west shores of the Dead Sea, a Bedouin shepherd discovered some caves with clay jars, containing leather scrolls with Hebrew writing, in them. He recovered some scrolls and tried to sell them to a cobbler (leather is good for making shoes), who referred the shepherd to an antiques dealer. Eventually the scrolls were recognised by a scholarly person, for what they are in 1947, which lead to excavations and many more scrolls. In total, 825 scrolls and many more fragments were found in 11 caves around the wadi. The scrolls contain various copies of the different books of what we refer to, as the Old Testament. Only the book of Esther was not found to date. Many of the scrolls are nonbiblical writings along the order of commentaries on the OT, paraphrases that expand on the Law, rule books of the community, war conduct, thanksgiving psalms, hymnic compositions, benedictions, liturgical texts, and sapiential (wisdom) writings.
Excavations pointed to a Jewish sect, the Essenes, living their ascetic lives in this area. They did not include rabbinical writing (the Talmud, etc) in their religious experience, but stuck to the Hebrew Canon of Bible books, known as the Old Testament. One could say, they were purists. Apart from studying religion, they also copied the books of their Bible. They occupied this area for the last 300 years BC until 70 AD, when they Romans lost their cool with the Jews.
The significance of the discovery, is that it provided a totally independent source, confirming the Masoretic text that was used over the ages by Christians and Jews alike, with reference to the Old Testament. This is the oldest and most complete copy of the Old Testament on record, to this date.
For a more complete coverage of the Dead Sea scrolls, you can read Wiki.
The picture shows an exhibition of what the jars containing scrolls, looked like. This is in a museum, on site, at Wadi Qumran.