Due to the rapid development of high-speed transportation and digital-network, the life pattern of modern people also has been rapidly deconstructed and re-organized. To respond such a flexible, multi-layered, and ambiguous period, various countermeasures have been studied in terms of modern architectural programs. As one of the solutions, activity diagrams are a methodology which creates an architectural space through a process of analyzing people's behaviors as well as re-organizing their systems. 
Modern architecture is already familiarized with the words 'program' and 'diagram'. Many architects throughout the world use these words as a design tool.
Therefore, we sought for 9 architects, regardless of nationality, who used their diagrams as aninnovative design tool, and selected 30 architectural works in which their diagrams were applied. Also, we interviewed them ontheir architectural design methodology through diagrams they are currently using.
With this, we could study out a diagram's inclusive meanings and roles within architecture. This book is published in the hope of being an architectural guide to modern architects who have to design relations.