The Hydrophilic-Lipophilic Balance (HLB) is a scale that measures the degree to which a surfactant is hydrophilic (water-loving) or lipophilic (oil-loving), crucial for Formulating emulsions and other Biphasic Systems. It helps in determining the right surfactant for a Specific Application, ensuring Stability and compatibility in formulations like cosmetics, pharmaceuticals, and Food Products.