Gertrude Bell's Arabian Diaries, published here for the first time, rank as one of the great travel narratives, carrying readers along on a desperate and heroic journey that foreshadows the emergence of the future imperial servant in Baghdad in the 1920s. Bell's adventures are the stuff of novels: she rode with bandits, braved desert shamals, was captured by Bedouins, and sojourned in a harem. Called the most powerful woman in the British Empire, she counseled kings and prime ministers. He colleagues included Lloyd George and Winston Churchill, who in 1921 invited Bell--the only woman whose advice was sought--to the Cairo Conference to "determine the future of Mesopotamia." She numbered among her closest friends T.E. Lawrence, St. John Philby, and Arabian sheiks. Editor O'Brien preserves B