This biography provides explanation of Louis Sullivan's importance as an architect. It includes a new introduction which provides corrections to the biographical data in light of six decades of research, and an authoritative revision of the list of buildings that includes information on buildings discovered after the book's initial publication, and details of those subsequently demolished. At beginning of 20th century, Louis Sullivan was virtually alone in championing progressive American architecture. He ferociously condemned the rampant neo-classicism brought on by the Chicago World's Fair of 1893, calling it "an appalling calamity". (The Architectural Traveller). He had one foot in the 19th century, another in the 20th - the Carson Pirie Scott building in Chicago, features a two-storey classical base embellished with cast-iron wreaths and tendrils, while the upper 10 stories are crisply modern, and represent the proto-skyscraper. Sullivan's genius lay in his ability to combine clean modern lines and techniques with the lush decorative flourishes of the nineteenth century.