Preface -- With its clutter of signs and ordinary lampposts, it looks like streets all across the country, but just down Pennsylvania Avenue in Washington, D.C., is the most important address in the world. In a monumental house conceived and built by George Washington, who almost lived to see it finished, every president since has carried his own burden through its halls, stood in awe of the gigantic East Room, has thrilled to its great pillars and stately façades, has spent sleepless nights tossing in its beds. The grand house, like the presidency itself, has both remained very much a constant and changed tremendously over the two centuries since John Adams made the mansion his own on November 1, 1800, with the very first night's sleep of a chief executive.