Vortex-Based Cosmology presents a unified theoretical framework in which spacetime, matter, fields, and cosmic evolution arise from a single underlying dynamical principle. The model describes spacetime as a non-orientable manifold with a global topology related to that of a Klein bottle. This topology naturally generates constrictions, cyclic return flows, and self-similar structures across all physical scales. Within this framework, vortices appear as fundamental, topologically stable configurations of the spacetime flow. Their interactions form the basis for interpreting elementary particles, gravitational effects, electromagnetic phenomena, and large-scale cosmic structures. Particle properties such as mass, charge, and spin emerge from geometric and topological features of vortex modes, while decays correspond to discrete topological reconfigurations. On cosmological scales, the model offers alternative interpretations of expansion, background radiation, and structure formation. Galactic rotation curves arise from the flow geometry of large-scale vortices rather than from dark matter halos, and cosmic expansion corresponds to the outflow phase of a global vortex instead of a singular Big Bang event. The non-orientable topology eliminates the need for singularities and inflation, providing a cyclic and self-sustaining cosmological picture. The work reconstructs classical phenomena—such as singularities, renormalization, vacuum energy, and information loss—as consequences of flow dynamics rather than as fundamental problems. It outlines the mathematical structure of the model, including topological charge, divergence-free flow, discrete vortex modes, and global return dynamics. This publication establishes a conceptual foundation for future mathematical refinement, numerical simulation, and empirical comparison. It is intended as a starting point for further development of a unified, vortex-based description of physical reality.