The Universal Functional Coherence Theory (UFCT) is presented in its canonical formulation, grounded on a minimal and testable mathematical core. The fundamental law is expressed as a reaction–diffusion equation with a quadratic dissipative term that incorporates irreversibility at the most basic level. An equivalent relaxation form is introduced to make the local attractor explicit, allowing direct evaluation of characteristic times and dimensionless control numbers. This layered structure keeps the main text conceptually simple while relegating technical machinery—variational principles, Lyapunov stability, operational definitions, and recovery of thermodynamic, relativistic, and quantum limits—to the appendices. Protocols for parameter estimation and a roadmap for simulation and experimental validation are outlined, positioning the UFCT as both mathematically robust and empirically approachable.