Operational Spacetime: Interactions and Particles provides readers with a basic understanding of the mutual conditioning of spacetime and interactions and matter. The spacetime manifold will be looked at to be a reservoir for the parametrization of operation Lie groups or subgroup classes of Lie groups. With basic operation groups or Lie algebras, all physical structures can be interpreted in terms of corresponding realizations or representations. Physical properties are related eigenvalues or invariants. As an explicit example, an operational spacetime is proposed, called electroweak spacetime, parametrizing the classes of the internal hypercharge-isospin group in the general linear group in two complex dimensions, i.e., the Lorentz cover group, extended by the causal (dilation) and phase group. Its representations and invariants will be investigated with the aim to connect them, qualitatively and numerically, with the properties of interactions and particles as arising in the representations of its tangent Minkowski spaces. Heinrich Saller is the author of Operational Quantum Theory I: Nonrelativistic Structures (Springer, 2006) and Operational Quantum Theory II: Relativistic Structures (Springer, 2006).