When Ludwig Mies van der Rohe left Germany for the United States, in the summer of 1938, he was fifty-two years old. He had practiced as an architect for over three decades: had published, lectured, and exhibited; had produced designs not only for Germany but for The Netherlands, modern-day Poland, Spain, the modern-day Czech Republic, Belgium and the United States; and had been a leader of the architectural community in his native land. Yet the book that accompanied his first retrospective exhibition, at The Museum of Modern Art in 1947, could nevertheless open with the remark, "Of all the great modern architects Mies van der Rohe is the least known." Despite the historical importance of Mies's architecture, this observation holds in certain respects, for Mies's Berlin work has never been fully explored. Outside the handful of manifesto projects and built works that have become famous, his German practice has tended to be seen retrospectively as but the first step toward the triumph o