The 24-foot (7.3-meter) scroll with the text of the Bible's Book of Isaiah had been in a dark, temperature-controlled room at the Israel Museum since 1967. It went on display two years earlier, but curators replaced it with a facsimile after noticing new cracks in the calfskin parchment.
The museum decided to put the scroll back on show for three months as part of Israel's 60th anniversary celebrations.
The priceless manuscript, written by a Judean scribe around 120 B.C., was in a long glass case Tuesday, its neat rows of Hebrew letters distinct and legible. President Bush, visiting Israel this week for the anniversary celebration, will be one of the first to view it.
The Isaiah manuscript was the only complete biblical book discovered among the Dead Sea scrolls, one of the great archaeological finds of the 20th century.
The ancient documents, which include fragments of the books of the Old Testament and treatises on communal living and apocalyptic war, have shed important light on Judaism and the origins of Christianity.
(See a time line of early Christianity.)
The Book of Isaiah is traditionally attributed to a prophet who lived in the eighth century B.C.
In the book, he calls for repentance, warns of impending doom, and offers an idyllic vision of the future: "They shall beat their swords into plowshares, and their spears into pruning-hooks. Nation shall not lift up sword against nation, neither shall they learn war any more."
(Related: "Underground Tunnels Found in Israel Used In Ancient Jewish Revolt" [March 15, 2006].)
Gem of the Dead Sea
Curator Adolfo Roitman called the Isaiah manuscript the "gem of the Dead Sea scrolls."
It is "one of the most important treasures of the Jewish nation, if not the most important," he added.
A far smaller fragment of another Dead Sea scroll will be on display at the Jerusalem convention center where Bush will be speaking along with other dignitaries.
The segment, also rarely shown, contains the text of Psalm 133, which reads: "Behold, how good and how pleasant it is for brethren to dwell together in unity."