Adolf Loos (1870–1933) was an Austrian architect and theorist who pioneered modernist minimalism and rejected decorative excess. His seminal essay Ornament and Crime (1908) argued that ornamentation was outdated, advocating for functional, unembellished architecture. His notable works, including the Looshaus in Vienna and Villa Müller, emphasized clean lines, geometric forms, and material honesty. Loos introduced the Raumplan concept, a revolutionary approach to spatial organization that influenced modernist interior planning. His ideas profoundly impacted 20th-century architecture, challenging traditional aesthetics and inspiring figures like Le Corbusier, shaping the foundations of modernism and functionalist design.