EDWARD R. MURROW worked in broadcasting, the most evanescent of all news media, and his tangible legacy is predictably small: scratchy radio tapes, blurred television films, a published collection of his pieces that occasionally can be found in used-book stores. Yet his actual legacy, the one that lives on in the hearts of journalists and listeners alike, remains remarkably large two full decades after his death. Not merely was he the greatest journalist ever to work in broadcasting -- indeed, the only "great" journalist broadcasting has thus far produced -- but he was for millions of Americans a figure of conscience, rectitude and professional integrity, who established standards against which reputable broadcasters still measure themselves and against which listeners and viewers still measure them.

This being the case, it is a real pity that the Murrow biography being represented as "definitive" comes close to being a case study in how not to write biography. Murrow: His Life and Times is a well-intentioned book by a woman whose admiration for her subject is intense, but the heavens do not contain enough good intentions to paper over the shortcomings of what A.M. Sperber hath wrought: her insistence on battering the reader with every trivial detail her research has uncovered, her interminable descriptions of individual broadcasts and political maneuverings at CBS, her inability to distill protracted episodes down to the core of their meaning, her cloying, cliche'-ridden, saccharine prose -- and, worst of all, her utter failure to analyze the style and content of Murrow's journalism. A lean, interpretive biography of perhaps 350 pages would have served Murrow just right; instead he is suffocated by one more than twice that length.

The broad details of Murrow's life and career are familiar to most people old enough to remember him; it is remarkable how little this vast accumulation of factoids manages to broaden our understanding of them. He was born in North Carolina in 1908, moved to the Pacific Northwest as a boy, and lived in a state of near-poverty that left him with a life-long sympathy for the deprived. He came to journalism somewhat by accident, after beginning adult life in jobs that encouraged his interest in public and foreign affairs, but once he got to CBS he took little time to show what he could do. His broadcasts from England during World War II -- "This . . . is London" -- brought the realities of the Blitz home to Americans with almost unbearable intimacy and had much to do with swinging American sentiment away from isolationism.

After the war came television, with which Murrow was never really comfortable but in which he nevertheless distinguished himself. See It Now, his news series for CBS, was probably the most serious and accomplished regular news program ever produced for commercial television; surely no one needs to be told that it was Murrow's See It Now program about Joseph McCarthy in March 1954 that crystallized public and senatorial opposition to the rogue elephant from Wisconsin. Gradually, though, television news came under the purview of the advertisers and entertainers, and there wasn't much of a place left for one so committed to true journalism as was Murrow. He did several fine documentaries for CBS Reports, most notably "Harvest of Shame," but when he had a chance to escape, he seized it: in 1961 he accepted John F. Kennedy's invitation to run the United States Information Agency, a job for which he was not really suited -- he belonged on the other side of the news -- but to which he gave his best efforts. In 1965 he died of lung cancer, killed off by the cigarettes that, along with his inimitable voice, had been his trademark. HE WAS at once the right man and the wrong man for his times. When he entered broadcast journalism, it was an infant medium with no preconceptions about how its business should be done. The instinct of those running it was that the news should be covered seriously; Murrow, with his training at the Institute of International Education and his wide acquaintance among leaders at home and abroad, was exactly the kind of young man CBS was looking for. During the war, when Americans were desperate for reliable information from overseas, Murrow gave them that and more: without ever trivializing the news, he gave it a human dimension, so that Americans understood the suffering and courage of ordinary Englishmen and then, after 1941, the ordeal their own sons and brothers were undergoing. Not merely that, but as head of CBS's European news operation, he recruited the best broadcast news team ever assembled: William L. Shirer, Charles Collingwood, Eric Sevareid, Howard K. Smith, David Schoenbrun -- they and their other associates remain, four decades later, the model of what broadcast news can do, and has not done since.

But then the war ended, and Murrow could see what was coming. "He thought it already apparent," a friend said, "that the expansion, commercialism and impending advent of TV were all going to make news increasingly the servant of entertainment and commerce." He was right. Though Murrow did make one accommodation to the new age -- his popular television program, Person to Person, which made him both a celebrity and a wealthy man -- but he never adjusted to its debased terms. In a speech delivered in the fall of 1958 he said: "It may be that the present system . . . can survive. Perhaps the money-making machine has some kind of built-in perpetual motion, but I do not think so. . . . We are currently wealthy, fat, comfortable and complacent. . ..Our mass media reflect this. But unless we get up off our fat surpluses and recognize that television . . . is being used to distract, delude, amuse and insulate us, then television and those who finance it, those who look at it and those who work at it, may see a totally different picture too late. . . "

Almost overnight, the man who had been in the right place in the right time became a pariah. He was a man of high, exacting standards in a business that had decided that standards were irrelevant. His old friends in the corporate offices still thought he was a hell of a fellow, but suddenly they couldn't find much air-time for him. His last years, both at CBS and at USIA, were not happy. His health was deteriorating, but what really pained him was that there was no longer a place for him. How poignant it is to read what he said in 1961, as he was leaving for Washington, to an apprehensive Richard Salant, who was moving into the leadership of the CBS News Division: "Dick, you're just where I was when I started. I wasn't a journalist either; but you love it, and that's that. All you have to do is love the news." But by 1961 there was no longer a place in the news for Ed Murrow; surely that, as much as the cigarettes, is what killed him.