A new integral method was devised for predicting the development of two-dimensional, incompressible, stationary turbulent boundary layers. This new method differs from the older integral methods in that it explicitly accounts for the turbulence via a characteristic turbulent velocity scale. A model of the turbulent kinetic energy integral equation is used to keep track of this turbulence scale. The model equation is developed on the basis of intuition, physical reasoning and some experimental evidence. In this new method the model equation is solved in conjunction with the momentum integral equation and the entrainment equation. A two-layer velocity profile is used. The law of the wall is assumed valid in the inner region and Coles' law of the wake is assumed valid in the outer region. The two profiles are joined by asymptotic matching; this gives an implicit equation for the skin friction. The predictions using this method are in excellent agreement with the measurements for fourteen different experimental boundary layers. (Author).