Clear as a Walker Evans photo: a biography of folk-humorist Will Rogers (1879-1935), who, like Cary Grant and Humphrey Bogart, grew into his mask, becoming the image of wry, genial common sense until his death. Yagoda (English/University of Delaware) offers an utterly thorough, brilliant taking-apart of the unique Rogers persona. Ronald Reagan, he tells us, gave ``an impressive Rogers impersonation in the White House'' and back in the 40's was thought to be a natural to play Rogers in the film bio—but Will Rogers, Jr., got the role. ``For there to be another Will Rogers today,'' Rogers says, ``he (or she) would have to combine...Johnny Carson, Mark Russell, Roy Rogers, Clark Clifford, Walter Cronkite, Bill Cosby, Bob Hope, Russell Baker, H. Ross Perot, and Walter Lippmann. It just can't happen.'' Yagoda finds Rogers to have been a divided being, a rather gleeful but sometimes despairing and angry youth who clammed up after marriage and became the model of ``unmatched stability, drive and contentment.'' One-quarter Cherokee, he rode the plains as a young cowboy, then took his mastery of the lariat and patter to the vaudeville stage, emerging as the Lincolnesque figure who ``never met a man I didn't like.'' Rogers went on to a rather bumpkin-ish career in silent movies; graduated to a kind of sheepishly patriarchal status in talkies; made records; then became a radio humorist, syndicated newspaper columnist, and crony of politicians while grabbing the ear of FDR and topping out as Hollywood's number-one star: An amazing, unforeseeable life. As a speaker about politics, he kept his knife sheathed, talking as if from the very pulse of the people during the Depression, and was finally seen by all as the apostle of decency and archetype of American wisdom. His interest in aviation led to his death in Alaska—and to the grief of a nation. So immediate you can scratch a match on his boot sole. (Photographs)