This catalogue presents the first comprehensive study of the Italian architectural drawings in the Cronstedt Collection in the Nationalmuseum, Stockholm, comprising 181 drawings dating from c. 1570 to c. 1630. Among them are original projects by Francesco da Volterra, Carlo Maderno and other Roman architects of churches, chapels, palaces, gardens and fountains, many constituting primary and almost unknown source material relating to late Mannerist and early Baroque architecture. Also included is a large corpus of plans, façades, and architectural details by French draughtsmen that meticulously document ancient monuments as well as buildings by the Renaissance masters Bramante, Antonio da Sangallo, Michelangelo and Vignola. The catalogue puts forward new proposals of identification and attribution in the light of recent scholarship, also based on a close examination of the materiality of the drawings (paper, medium, technique, mounting). Comparative illustrations and a photographic catalogue of the watermarks complete the volume.