Albert Einstein was a German-born theoretical physicist. He is best known for his theory of relativity and specifically mass–energy equivalence, expressed by the equation E = mc2. Einstein received the 1921 Nobel Prize in Physics "for his services to Theoretical Physics, and especially for his discovery of the law of the photoelectric effect.”

Einstein's many contributions to physics include:

Ø Special theory of relativity, which reconciled mechanics with

      electromagnetism

Ø General theory of relativity, a new theory of gravitation which added the

      principle of equivalence to the principle of relativity  

Ø Founding of relativistic cosmology with a cosmological constant  

Ø The deflection of light by gravity and gravitational lensing  

Ø The photon theory and wave-particle duality from the thermodynamic

       properties of light

Ø The quantum theory of atomic motion in solids

Ø The semiclassical version of the Schrodinger equation

Ø Relations for atomic transition probabilities which predicted stimulated

       emission

Ø The quantum theory of a monatomic gas which predicted Bose-Einstein

      condensation

Ø A program for a unified field theory by the geometrization of physics.