Abstract Understanding the equation of state (EOS) and strength properties of selected materials is fundamental to predicting material behavior under extreme conditions—ranging from planetary core dynamics to high-velocity impacts and explosive loading. This article reviews the theoretical frameworks, experimental methodologies, and empirical data for a curated set of materials: metals (copper, tantalum), ceramics (silicon carbide, boron carbide), polymers (PMMA), and geological reference materials (quartz, granite). We examine how coupled EOS-strength models (e.g., Mie-Grüneisen with Steinberg–Cochran–Guinan, or Johnson–Holmquist for ceramics) improve prediction fidelity beyond standalone pressure-volume relationships. 1. Introduction: Why Coupling EOS and Strength Matters The equation of state describes a material’s volumetric response to pressure and temperature (e.g., ( P(V,T) )). Strength properties, conversely, govern resistance to shear deformation—yield stress, hardening, and failure. In many engineering scenarios (e.g., armor penetration, planetary accretion, hypersonic flight), pressure and shear occur simultaneously. Using only a hydrostatic EOS ignores deviatoric stresses, leading to catastrophic underprediction of spall, fracture, or adiabatic shear banding.