Using statistical methods analogous to those used in the kinetic theory of dense gases, conservation equations and constitutive equations are derived for the flow of an idealized granular material of uniform, rough, inelastic spherical particles. Simple forms for the singlet and pair velocity distribution functions are employed to study the effects of particle rotary inertia in the specific case of Couette flow of such materials. A constant coefficient of restitution e is used to characterize the inelasticity of the particles and a roughness coefficient \(\beta\) is adopted to characterize the effects of surface friction in collisions between particles.