When the Tuscan city of Pisa commissioned David Chipperfield to create a master plan that would bring new vitality to this historic place on the Arno, an exhibition of a selection of work produced by him in the last 25 years was also invited. Chipperfield chose "Form Matters" as a title for the exhibition, as "Form" and "Matter" are all-important key elements of the language of architecture. We asked him to lead the way through the models, drawings and photographs to explain his designs, which were realized all-over Europe, China, Japan, the United States and Mexico and to give us an accounting of his creative direction at each stop.