Two dates burn fiercely in the memory of millions of Americans: November 22, 1963, and September 11, 2001. These two tragedies bracket Unafraid, a story grounded in a simple question: What if the fatal bullet fired on that sunny Dallas afternoon had veered three inches off target? Unafraid lays out a compelling answer, rich with the public adventures and private dramas of twentieth-century icons—from J. Edgar Hoover to the Beatles—played out on...