Show Business: I Do Believe in Control

Cosby is a man who gets laughs -- and results -- by doing things his way

It is midmorning in Las Vegas, and already the desert heat is shimmering wetly on a running track not far from the casino strip. Here Bill Cosby is hurling himself through a series of sprints, his sturdy 6-ft. frame showing the form that won collegiate championships three decades earlier. The stride is long and smooth, and the pace is brisk through 300 meters (43 sec.) and 600 meters (1:48). Cosby beats his target times and beams with satisfaction. He rewards himself with a Cuban cigar the size of a relay baton and sets a faster goal for tomorrow.

At 50 Cosby...