Letter From The Editor.- Letter From The Editor.- Architecture, Mathematics and Perspective.- Giotto and Renaissance Perspective.- Perspective, a Visionary Process: The Main Generative Road for Crossing Dimensions.- Perspective in a box.- Juan Bautista Villalpando and the Nature and Science of Architectural Drawing.- Perspective versus Stereotomy: From Quattrocento Polyhedral Rings to Sixteenth-Century Spanish Torus Vaults.- The Sunlight Effect of the Kukulcán Pyramid or The History of a Line.- Some Adaptations of Relativity in the 1920s and the Birth of Abstract Architecture.- Book Reviews.- The Mirror, the Window, and the Telescope: How Renaissance Linear Perspective Changed Our Vision of the Universe.- The Geometry of an Art. The History of Perspective from Alberti to Monge.- Forma y Representación. Un Análisis Geométrico.