Oh-oh. We'd better get back."" It is election night 1948. Tom Dewey--racket-busting Manhattan D.A., two-term New York governor, now in his second, sure-fire bid for the presidency (""To err is Truman,"" went the pun)--has just heard, at a ritual dinner with friends, the first Connecticut returns. And, with an armory of eyewitness material like that, Smith vindicates his choice of this unpromising subject for a full-length, 600-page biography. You may not care whether Dewey was ""the man on the wedding cake or the man on the white horse,"" or wonder what-might-have-been, but by the end of Smith's introductory chapter, which scatters morsels of Deweyana through the reconstruction of that Great Upset election night, plain curiosity hooks you. So how did this stiff, fastidious little guy become the scourge of Lucky Luciano and the like? Why did he hate Robert Taft so much that, in front of women reporters, he resorted to barnyard language? Was he really such a whiz as governor? Still: Tom Dewey's ""Times""! That's a little problematic--but not ineffective. To Dewey's tidy upbringing in Owosso, Michigan, Smith parallels Luciano's boyhood on the Lower East Side; elsewhere, he traces other roots, other courses--including that of the Republican Party, starting with the 1912 Bull-Moose/TR-conservative/W. H. Taft split. (Dewey's fiercely Republican father was a Taft-hating Bull Mooser.) And, what is very much a production is also overwritten and overcolored (though less so as the book progresses). Nonetheless, the text crackles with intellectual vitality and brims with criminal, political, and governmental detail. Dewey escapes from Owosso, via a stipend for voice study (voted by wife-to-be Frances), and enters Columbia Law; relinquishes hope for a singing career (after a laryngitis-plagued debut), makes a small name in local Republican politics (the scrappiness, the doggedness), becomes chief assistant US attorney (the organizational skill, the unabashed conceit)--and, at 30, is in pursuit of gangsters. As special prosecutor, he goes after the rackets, ""from artichokes to pinball""; gets Luciano on prostitution (!); nets all the major policy operators in one big raid; and shakes down the pols himself before accepting the 1937 Fusion nomination for D.A. (Pastrami? He'll try it--""on whole wheat with mayonnaise."") Still to come, of course, are the gubernatorial and presidential campaigns (with, in '48, a deft foreshadowing of that unexpected defeat); Dewey vis-Ã -vis LaGuardia, Dulles, Willkie, Taft, Nixon; the socially progressive, fiscally conservative governorship (antidiscrimination legislation, a veto of stiff drug penalties; a full till); hang-in-there advice to Nixon (the Checkers speech); and--for a tender, surprising close--an autumnal romance with Kitty Carlisle Hart. If only for the contemporary political milieux, outstanding--but ultimately a very interesting study of a basically uninteresting man.