'Form Follows Function' — coined by Louis Sullivan (1896, in his essay 'The Tall Office Building Artistically Considered').

• Sullivan was the 'father of modernism' and mentor to Frank Lloyd Wright.
• The phrase means: the shape/appearance of a building should be primarily dictated by its intended function or purpose.
• Associated with the Chicago School of architecture — early skyscraper design using steel frame construction.
• Influenced later Modernism, Bauhaus, and the International Style.