The Theory of the Absolute (ToA) is a formalism for describing space, time, and the propagation of light, based on the assumption of a single absolute Euclidean space and a local field time. Within ToA, time is not a property of spacetime geometry but a secondary quantity, determined by local parameters of the gravitational field. The local rate of time flow depends both on the gravitational field and on the motion of an object relative to the local mass distribution, rather than on global spacetime transformations. Absolute time serves solely as a reference parameter that orders events within absolute space and does not constitute a directly measurable physical quantity. The speed of light remains locally constant and equal to c in every region of gravitational interaction. Observed frequency shifts and changes in photon energy are interpreted as consequences of differences in local field time rates, rather than as effects of spacetime transformations or spatial expansion. The model remains consistent with local experimental observations, including the Michelson–Morley experiment and the readings of atomic clocks onboard satellites within the Global Navigation Satellite System (GNSS). At the same time, it offers an alternative interpretation of cosmological observations, such as the apparent superluminal recession of objects and large-scale redshifts, without invoking spacetime expansion, dark energy, or dark matter. The paper formulates the axioms of the theory and presents a local formalism describing the motion of matter and light. Finally, empirically testable predictions are discussed, allowing the Theory of the Absolute to be distinguished from standard relativistic formalisms.