Book excerpt: From the late 1940s to the mid-1970s, Richard Nixon was a polarizing figure in American politics, admired for his intelligence, savvy, and strategic skill, and reviled for his shady manner and cutthroat tactics. Conrad Black, whose epic biography of FDR was widely acclaimed as a masterpiece, now separates the good in Nixon -- his foreign initiatives, some of his domestic policies, and his firm political hand -- from the sinister, in a book likely to generate enormous attention and controversy. Black believes the hounding of Nixon from office was partly political retribution from a lifetime's worth of enemies and Nixon's misplaced loyalty to unworthy subordinates, and not clearly the consequence of crimes in which he participated. Conrad Black's own recent legal travails, though hardly comparable, have undoubtedly given him an unusual insight into the pressures faced by Nixon in his last two years as president and the first few years of his retirement.