Santiago Calatrava studied both architecture and civil engineering before setting up his dual-disciplinary practice in Zurich in 1981. His distinctive designs are generated by an inquisitive and innovative approach to structure and form. He is fascinated by structure in nature, and with the inherent movement of natural forms. Calatrava has observed that 'engineering is the art of the possible': the ideas behind his buildings and bridges are often developed from experimental sculptures addressing balance, tension and motion. This monograph includes an interview with Calatrava and looks at a selection of twenty-one projects from the early eighties to works currently on site, illustrated with photographs and construction drawings. Illustrated essays by Dennis Sharp and Anthony Tischhauser explore Calatrava's working methods and his theoretical preoccupations - tracing the development of Calatrava's unique design language from his initial investigations into folding mechanisms to the present day.