This book Bivariate Ageing Classes and their Properties gives the definitions of the bivariate stochastic ageing classes of life time distributions and their respective duals. Some new classes of the bivariate stochastic ageing classes are introduced. Discrete version is also presented. Stochastic properties such as convolution, preservation under Poisson shock models of almost all the bivariate stochastic ageing classes are given. Convolution and Preservation of the bivariate stochastic ageing classes and their duals are presented. Moment inequalities have been determined. Moment inequalities for the dual version of these ageing classes of life time distribution have also been established.