Harry Reasoner's shirtsleeves memoirs of his ""first twenty-five years in television news""--tantamount to the ""first twenty-five years of television news""--leads off with some great, base-touching one-liners, settles into a fascinating backgrounder on the very early days, and then just sort of dips and swoops through the Big Time years. But the offhand Reasoner charm makes for easy going, regardless; and there are those heroic beginnings--when TV news was trying to be what the newsreels never had been, a real news medium. ""We had to invent things before they were simple."" So Reasoner, at KEYD-TV, Minneapolis, in 1954 (""I became the news director. I was the news department""), got cheap-and-easy sound by recording voices with an audio tape recorder, and filming, with a silent camera, the person who wasn't talking. But it was at CBS News, from '56 on, that Reasoner and other then-unknowns ""who knew and liked film, who knew and understood what Don Hewitt wanted, who felt at home in a thirty-second report,"" began to go out on the stories with the cameramen; and then, as the evening news became more important, with the likes of Doug Edwards and Bill Downs. Nothing undignified--still: ""We wanted to be a CBS News Correspondent. Good Lord, that was Murrow's title."" And in '57, Reasoner made it: ""The first to be named out of television news."" How It Was: an eight-o'clock call at home, in Connecticut (six small children, a big mortgage); a plane from La Guardia late that night; a morning charter to the site; and ""try to figure out how to make a story of the incident that justified all the charters and rushing and sleeplessness,"" ""to get something from the scene that could illuminate the story for television without corrupting it for journalism."" And catch that evening's broadcast. In Florence, S.C., after a stray-bomb incident, Reasoner invented the Barber Shop Device: ""some real, evocative comments,"" in five or six minutes. After those ""fireman days,"" the fall-off begins--with Little Rock, which Reasoner touts as a television story, then tells as History--as a victory for the ""moderate bourgeoisie."" And then it's a motley: professional pique (""no presence""?); domestic tribulations (eventually, a divorce); unnamed other women; always a ""co-something"" (discretion re Barbara Walters); LBJ (""Too bad, in foreign affairs, he didn't have more confidence in what he instinctively knew""); 60 Minutes (the grind, the satisfaction); leaving CBS (""heartsick"") after seven years--and coming back. Says his new wife, after the first, burial-of-Pope-Paul broadcast: ""You sounded inappropriately joyous."" So: lots of zest, shrewd pacing, spotty reporting. But even if you're disappointed, you won't be bored.