During the talk, I will review the state of the art concerning the dynamics of spreading. For low viscosity liquids, I will investigate the potential link between Kramer's treatment of rate processes and the molecular-kinetic theory of wetting. The results of recent large-scale simulations of dynamic wetting will be used to illustrate and validate our analysis. We find that both theories predict that, for a given driving force, the velocity of the contact line is inversely proportional to the viscosity. They also predict that the velocity will depend with a negative exponent on the strength of solid-liquid interactions, which for simple systems can be represented to good approximation by the reversible work of adhesion Wa0.