Phase separation is the spontaneous process by which a homogeneous system separates into two or more thermodynamically distinct phases, driven by a reduction in free energy. This academic concept investigates the underlying mechanisms, kinetics, and resulting morphologies of such demixing phenomena, exploring how factors like molecular interactions, composition, temperature, and pressure govern the formation and stability of interfaces between the separating phases. Its significance lies in its fundamental role across diverse scientific disciplines, including materials science, chemistry, biology, and physics, underpinning phenomena from protein condensation and polymer morphology to alloy formation and critical phenomena.