In a world where sustainability, ecology, collaboration and performance are common concerns, “joining” is a keyword, expressing the idea of an integration of knowledge, efforts and processes aimed at a better future. The CAADFutures 2009 conference thus intends to join professional and scientific reflections, with the notable input of new disciplines that are also concerned with digital design, such as industrial design and civil engineering. As a result, a vivid dialogue is established between different cultural approaches, computational methods and philosophical positions. The field of computer-aided design is faced with many challenges. CAADFutures 2009 addresses the search for new paradigms for sustainable design, the issues derived from the “digital thinking” embedded in current CAD systems as opposed to the needed “design thinking”, and many more pressing questions such as those of heritage, advanced geometry and parametric design, CAD education, virtual environments, interaction and new technologies, simulation, building performance, rapid prototyping, management, collaboration and ideation.