A dislocation array method of two-dimensional stress analysis has been used to interpret commonly-observed features of craze growth in glassy polymers. It is deduced from the lack of deviation of craze pairs that the tensile stress across an air craze is more than 90% of the applied stress. Craze interactions occur at an early stage of growth when their penetration normal to the free surface exceeds 20% of their separation in the direction of the applied stress. It is suggested that the growth kinetics of crazes are controlled by the potential energy changes in the surrounding elastic material, which in turn are affected by the geometric interactions of crazes.