Though appallingly mismatched -- sexually, emotionally, politically -- the scheming nephew of Napoleon I and his headstrong Spanish consort had each cultivated in childhood a dream that thoroughly jibed with the ambitions of the other. A remarkable collusion of happenstance and ingenuity carried them to the throne. Once in power, Napoleon III and Euge?nie set out to revive a glittering and decadent Napoleonic gloire. But while they were designing the Paris of today, with its magnificent parks, boulevards, and architectural wonders, they were also dreaming up the Mexican fiasco responsible for poor Maximilian's death. They were to direct the course of our own time as well, for their disastrous foreign policies contributed to the rise of a Germany that would cause two world wars.