The book Time-Based Design Paradigms, from the LEM_ Design International series, explores the relationship between time and the design of spaces. The ongoing digital revolution and the recent pandemic have shown that the temporal dimension of spaces is a horizon that has yet to be strongly explored. In the future it is increasingly likely that it will be the forms of time, rather than those of space, that will undergo the most interesting innovations and transformations. Within the LEM (Landscapes, Environments and Mobility) section of the Design Department of the Politecnico di Milano, a group of professors and researchers, together with some international colleagues, have tried to investigate which forms of time will increasingly impact spaces: those of memory, of the everyday, of the extraordinary, of the future, of terrestrial and astronomical spaces, etc. The essays explore time: as measurements, adaptations/compositions, memories, machines and technologies, identities, narratives, sensitivities in an increasingly globalized and wrapped world.