At the end of the 19th century, Charles Martin Crandall, a cricket equipment manufacturer, gave his daughters, who were recovering from scarlet fever, a batch of the small wooden boards he used in his factory to pack his products. Seeing the girls' enthusiasm, the doctor treating them asked for a sample of this improvised toy, and Crandall became convinced that there was a business opportunity there. This is the origin of Crandall Blocks, one of the first construction toys that allowed children to assemble the pieces, not just stack them. Building is a primal impulse, one of the first activities children engage in, perhaps on par with speaking or walking. A few small boards or cardboard boxes are enough to awaken the architect within us all. And that is what this catalog is about: the evolution of construction toys that began to be marketed in the 19th century and their relationship with modern architecture. Le Corbusier, Gropius, and Frank Lloyd Wright recognized the importance of these toys in their development. And as collector Juan Bordes points out , these toys faithfully recorded – and in a surprisingly short time – the main advances of the most avant-garde architecture, making its achievements, literally, child's play.