Model experiments have been conducted on a series of alumina samples in which the microstructures have been tailored to conform to the classical configurations depicted in the models of final-stage sintering. Simultaneous measurements of sintered density, grain size, pore number density and pore size distribution were made as a function of sintering time at constant temperature (18500C). The data conformed to a model of grain-boundary-diffusion-controlled densification. Atom flux equations for grain-boundary diffusion transport and lattice diffusion transport were deduced from the data. The number of pores per unit volume was identified as the most critical factor influencing densification kinetics.