Guarini was talented in many areas and was considered a philosopher, mathematician and theorist but not an artist having had no experience of drawing. This changed when he became involved in the architectural profession through studying books and staying in theatine priest monastries all over Europe - from Rome to Venice, Milan to Veneto, Sicily to Paris culminating in a longer sojourn in Turin. He effortlessly blended architecture and geometry, and invented his extraordinary style by introducing building practices from northern Europe such as stereotomy and ribbed vaults deriving from Gothic buildings, into the Italian architectural tradition.With Guarini, visual perception becomes the essential element in architecture, together with the relationship between light and space, resulting in completely novel buildings such as the church of San Lorenzo and the Palazzo Carignano located in Turin, an astounding prototype of a princely residence. This book is a product of a seminar organised in 2002 by Centro Internazionale di Studi di Architettura Andrea Palladio and supported by the Compagnia di San Paolo, and is the most complete and up-to-date analysis of the work of this great architect, thanks to the scientific contributions of today's most important scholars and experts.