PBS Books, in collaboration with WETA in Washington D.C., interviews Beverly Gage, professor of 20th-century American history at Yale University and author of “The Day Wall Street Exploded.” Her new biography, “G-Man: J. Edgar Hoover and the Making of the American Century,” explores Hoover’s life and career, from his birth in 1895 to a modest Washington civil-service family to his death in 1972.