Walter Cronkite's 19-year tenure as anchorman of the CBS Evening News was an uncanny match of man and era. Two generations of Americans came to rely upon his presence in the CBS television anchor chair in times of war and crisis, scandal and celebration. His was a forthright, solemn presence in a time when each new dawn brought with it the prospect of nuclear annihilation or a second American civil war. Yet the master journalist was also a master performer—Cronkite was able and quite willing to display a flash of emotion or anger on the air when it suited him; this combination of stoic professionalism and emotional instinct earned the broadcaster two enduring nicknames: the man known familiarly as "Uncle Walter" was also called "The Most Trusted Man in America." When Cronkite closed the Evening News each night with his famous sign-off "And...