A Dutch artist, designer, and writer, Theo van Doesburg was a central figure in the De Stijl movement, which sought harmony and order through pure abstraction and geometric form. Working closely with Piet Mondrian and other avant-garde artists, he promoted a vision of art that integrated painting, architecture, and design into a unified modern aesthetic. His bold compositions of lines, rectangles, and primary colors helped define the look of early modernism and continue to influence art, design, and architecture today.