Amancio Williams: AP205 is a richly researched architecture book exploring the work of Argentine modern architect Amancio Williams (1913–1989), a key figure in Latin American modern architecture. Best known for the iconic Casa sobre el Arroyo, also called Casa del Puente (Bridge House), Williams produced a wide body of visionary projects that extended far beyond his few built works. Drawing from an extensive archive of drawings, photographs, models, and correspondence donated to the Canadian Centre for Architecture in 2020, this publication features new research by architectural historians and practitioners. Their essays offer fresh perspectives on Williams’ work, examining its social, material, and political dimensions and situating his practice within contemporary architectural discourse. Thoughtful, scholarly, and beautifully considered, Amancio Williams: AP205 is an essential volume for architects, designers, students, and collectors of modern architecture books.