No figure in American public life has had such great expectations thrust upon him and fallen short of them so quickly. But Ted Kennedy, the gregarious, pudgy, and least academically successful of the Kennedy boys, became the most powerful senator of the last half century and the nation's keeper of traditional liberalism.

As Peter S. Canellos and his team of Boston Globe reporters show in this intimate biography, Ted witnessed greater tragedy and suffered greater pressure than his siblings. He inherited a generation's dreams and ambitions, and was expected to help confront his...