Referred to in his time as "the Pretender" and "the sphinx of the Tuileries," Louis Napol on Bonaparte--the nephew of Emperor Napoleon I of France and himself ruler of the Second Empire (1852-1870)--so managed the manufacture of his public image and the masking of his private self that he is, ultimately, unknowable to this day. From the mysterious circumstances of his conception in 1807 to the strange events of his downfall in 1870 and death in...