Gene Siskel (1946-1999) and Roger Ebert (1942—) are to film criticism what Arnold Palmer and Julia Child were to golf and cooking respectively. They popularized a formerly stuffy discipline and made it accessible to masses of people. Long after Bosley Crowther, Pauline Kael, and other highbrow critics made reviewing movies an art form, this Mutt and Jeff duo, through their nationally syndicated television program, made it a spectator sport.

Siskel and Ebert established their critical bona fides writing for rival Chicago tabloids. They began their strange odyssey together in 1975, when producers at PBS station WTTW invited them to co-host a weekly film review program. Though initially reluctant, the two men eventually were persuaded that their mutual hostility might make for good television. The series began its run under the name Opening Soon at a Theater Near You and was wisely retitled Sneak Previews.

The show's...