A.M. Rosenthal, a brilliant, demanding editor who lifted The New York Times from economic doldrums in the 1970s and molded it into a journalistic juggernaut known for distinguished reporting of national and world affairs, died Wednesday at age 84. He died of complications from a stroke he suffered two weeks ago, the Times said. Rosenthal, known as Abe, spent virtually all of his working life at the Times, beginning as a lowly campus stringer in 1943. He rose to police reporter, foreign correspondent, managing editor and finally to the exalted office of executive editor, a post he held for nine years beginning in 1977. "Abe was a giant among journalists," retired Times publisher Arthur Ochs Sulzberger said in a statement. "He was a great editor with extraordinary loyalty to his troops."