The origination of high-entropy alloys and high-entropy materials will be discussed, as well as the concept of entropy, all kinds of entropy (e.g., Shannon entropy and configuration entropy); the current developments in high-entropy materials; the four core effects ((1) high-entropy effect thermodynamically, (2) slow diffusion effect kinetically, (3) severe lattice distortion structurally, and (4) cocktail effect for the properties); the breaking of balance between material strength and ductility; the breaking of performance limits of traditional materials; and the breaking of balance between physical and mechanical properties.