RABBI AKIBA'S MESSIAH - THE ORIGINS OF RABBINIC AUTHORITY by Dan Gruber, 288 pages, $20 Because of its long-term consequences, the Bar Kokhba Revolt may well be the greatest tragedy in Jewish history. The disaster was compounded by the fact that Rabbi Akiba, the father of rabbinic Judaism, proclaimed Bar Kokhba, the leader of the rebellion, to be God's Anointed, the Messiah. As Franz Rosenzweig asked, "Why did even the wisest teacher of his age fall for the false messiah, Bar Kochba, in the time of Hadrian?" This book answers that question. Akiba's proclamation appears to be a well-reasoned decision that was completely consistent with the whole thrust of his life ­ the establishment of rabbinic authority over all Israel.