Thinking the Useful in the Useless. For a Project of the Margin[al]’s Stratification. The useful works on the difference and produces marginality, the contemporary condition. The margin[al] is the product of the crisis in the spaces, a reality often surrender physically and conceptually invisible, now exploded. The quantity and quality of the phenomenon requires an update of the design tools for the transformation of the existing. Thinking the useful in the useless means to consider the marginality in a positive way, as a space significant in itself, a material of the architectural and urban design to consolidate in its figurative and functional role. In order to not reduce it as invisible or only separation between realities, you need to do to earn syntactic and semantic thickness to the margin[al] space, taking it as a projectual’s problem and theme. It is the possibility of building an architecture of the marginal spaces through the architecture of the margins and their thicknesses. The projectual ways investigated are the stratification of void, matter and time, within a geographic strategy that works by systems and mutual relationships between the parts of the architecture-city-territory.