The Mohr-Coulomb Criterion is a fundamental concept in soil and rock mechanics that describes the shear strength of materials. It states that the shear strength is a function of the normal stress acting on a failure plane and the material's cohesion. This relationship is often represented graphically using the Mohr Circle, which helps visualize stress states and failure conditions. The criterion is expressed mathematically as τ = c + σ tan(φ), where τ is the shear strength, c is the cohesion, σ is the normal stress, and φ is the angle of internal friction. This model is widely used in geotechnical engineering to predict failure in slopes, foundations, and retaining structures.