This book provides the idea of future technology based on the laws of quantum mechanics for example quantum teleportation, quantum computation. It includes the concept, definition, characteristics and detection of nonclassical states as well as entangled states. Wigner function for Two mode electromagnetic waves is developed and it is exposed to detect nonclassicality and entanglement. It covers the computation of Weyl ordered operators using Wigner function. It also contains the generation of two mode squeezed state and maximally nonclassical state by the application of inverse of boson operators.