This paper focuses on the latent spatial philosophy in Heidegger’s ‘Being and Time’, highlighting a key aspect of the Heideggerian oeuvre that has mostly been overlooked by commentators. It outlines the concept of an original spatiality of being that is opposed to the philosophies of space in both physics and Cartesian metaphysics. Through an elaboration of the essentially relational character of Da-sein, it is argued that Heidegger’s vocabulary in ‘Being and Time’ yields an onto-topology that shows Da-sein’s primary spatial embeddedness (...) in the world. Finally, the paper argues that Heidegger’s concept of spatiality remained cursory due to its residual existentialist focus. In this context, it attempts a re-evaluation of its intellectual trajectory within the realm of the Spheres project. (shrink)