In this book in addition to introduce Mock theta functions of order three,five and seven,The convergence of mock theta functions of order three, five and seven to an irrational number at an infinite points is discussed.more over the Irrationality behavior of four of the Ramanujan’s infinite series,and three of the G.N Watson Mock theta functions of order three at infinite points is also discussed. The applications Mock Theta function in Connection with characters of infinite dimensional Lie super algebras and conformal field theory is also introduced.