American architect. Sullivan studied in Boston and worked for Frank Furness in Philadelphia, before joining the engineer Dankmar Adler in 1880, where he became a partner in 1883. In the late 1880s they built steel -framed skyscrapers that combined Adler’s engineering skills with Sullivan’s decorative genius. His stylised forms derived from the Gothic Revival, yet they offered a radical new style for modern buildings and constituted a uniquely American Art Nouveau. Sullivan’s retrospective explanation of his ideas, the System of Architectural Ornament (1924), reveals an element of mysticism.