Structural Alignment presents a public theoretical model for understanding how adaptive systems move toward consequence before visible failure appears. The book defines a causal sequence through which signal becomes reduction, reduction becomes divergence, divergence becomes accumulation, accumulation approaches threshold, and threshold becomes consequence. It separates continuation from validity, correction from feedback, presence from authority, execution from legitimacy, trace from proof, and resonance from validation. Written across human, biological, organizational, institutional, technological, and AI contexts, this work argues that consequence is late. A system may still function, explain itself, and continue while the producing layer has already begun to lose fidelity. This book does not present an audit protocol, certification method, checklist, or implementation manual. It offers the public model of Structural Alignment: intervention before consequence hardens into visible form.