This book discusses an emerging approach to architecture in which building performance is a guiding design principle. This architecture places broadly defined performance above, or on a par with, form-making; it utilizes digital technologies of quantitative and qualitative performance-based simulation to offer a comprehensive new approach to the design of the built environment. In this new information- and simulation-driven design context, the paradigm of performance-based design can be approached very broadly — its meaning spans multiple realms, from spatial, social and cultural to purely technical (structural, thermal, acoustical, etc.)