Architecture exists in time. This statement may appear to be a truism but this is not the way in which architecture is typically conceived. It is not acceptable to conceive of architecture within the abstract context of stasis, nor to consider the architectural project ‘finished’ upon the completion of construction. Praxis must engage deeply with the dynamic conception of architecture within an evolving context, throughout the life of a building in time, and as animated through occupation and constructive perception. This paper provides a theoretical overview of time as it relates to architecture and philosophy. An architecture of time designs the conditions for interaction between user and environment, resists the crutch of formal autonomy, and finds novelty through engagement and the faith in the ability of the user to appropriate the space in unexpected and serendipitous ways. In this way architecture becomes a medium for the creative agency of time.