This review presents a discussion of the supercritical thermolytic coal extraction studies carried out at UC Davis. Extraction rates of bituminous coal with t-butanol were determined by continuously measuring the spectrophotometric absorbance of the effluent from a fixed-bed, differential flow reactor. At temperatures below 300°C compounds are extracted by a physical process, and above 300°C by thermal decomposition reactions. When hydrogen-donor tetralin is added to the solvent, the conversion increased substantially due to the stabilization of free-radicals by hydrogen. A kinetic model was developed to describe the free-radical mechanism of coal thermolysis, both in the presence and absence of a hydrogen-donor solvent. Free-radical reactions are supposed to occur on the solid coal surface and in the liquid film near the surface. The proposed mechanism is consistent with a reaction kinetics model with first- and second-order terms. The second-order term is a measure of the effect of the hydrogen donor.