A hydrostatic tidal model is presented which can successfully account for the two major features of lunar asymmetry. These are the observed offset between the centre of figure and the centre of mass, and the preferential distribution of lunar maria on the earthward side of the moon. The model requires that the following three processes occurred at the Roche stability limit: (a) formation, (b) petrological differentiation to give a mantle and an approximately 100 km thick crust, and (c) rigidification of the distorted mantle. We further demand that the mantle-crust boundary retain its distorted shape over the subsequent recession of the moon from the earth. Persistence of this distortion on a time scale of the order of one billion years can only occur if the upper mantle has a very high viscosity: this may be a physically implausible requirement. An extension of this model to consider the influence of asymmetric tides on crystal-liquid differentiation in a converting moon remains open for exploration.