The Sum of All Fears -
The title is a reference to nuclear war and to the plot by the novel's antagonists to reconstruct a lost nuclear weapon. The title comes from a Winston Churchill quote serving as the first of the novel's two epigraphs:
Why, you may take the most gallant sailor, the most intrepid airman or the most audacious soldier, put them at a table together—what do you get? The sum of their fears.
— Winston Churchill