Abstract: In a method and apparatus for recovering oil products from oil shale and like materials, controlled amounts of raw oil shale are delivered into an upper inlet of a downwardly sloping retort chamber that is constructed as readily portable. The raw oil shale is first moved in a direction countercurrent to gravity flow and crushed in the retort chamber by means of a rotating member that also serves to retain the oil shale in the retort chamber until a satisfactory recovery is completed. The crushed oil shale is confined to a relatively thin, downwardly moving layer in contact with a heated, inner, annular wall surface and moves by gravity flow between the inlet and a lower outlet to produce oil product vapors that rise to an upper portion of the retort chamber. The moving layer of the oil shale becomes spent as it passes through the retort chamber and finally is selectively discharged through the lower outlet.