This book develops a primitive-free reconstruction of physical description from the requirement of admissible closure: no structure is admitted unless its absence renders prior closure undefined. Beginning with Undefinedness, quotient closure, diagnostic completeness, compression, and regeneration, it defines Unified Substrate Closure as the invariant role required for predictive stability, not as substance, medium, ontology, or background. From this closure object the work derives a single master constraint whose controlled regimes yield propagation, ordering, localization, coupling, effective field grammar, gravity, and cosmological drift as induced outputs rather than assumptions. Empirical results are treated only as a tribunal gate: fixed predictions, declared nulls, scan discipline, negative controls, and failure conditions test applicability but never manufacture ontology. The result is an austere closure-first architecture for physics without primitives.