This project is well organized review of what is superconductivity, properties, some applications,rnand advantages of superconductors over ordinary conductors. The superconductingrntransition temperature (Tc) and the superconducting order parameter _(0) arerndetermined employing the quantum field theory double time Green function technique andrndiscussed using the well known BCS theory. The relation of Tc with the density of cooperrnpairs N(0) and interaction potencial V(0) together called electron coupling constant (_el)rnis shown graphically and discussed. Similarly the temperature dependence of the orderrnparameter _(T) as a function of temperature (T) is shown graphically and discussed asrnwell. For further or extensive studies on superconductivity, this project would be used asrna base line.