Abstract: A closed self-contained system (method and apparatus) for efficiently extracting oil and other hydrocarbons from oil-bearing hydrocarbonaceous solid material, which may be preheated to remove water and hydrocarbons which vaporize below about 600.degree. F., is advanced in the form of discrete individual pieces along a pathway in a substantially evacuated zone (e.g., less than 50 torr) while in the presence of heat energy sufficient to raise the temperature of the shale (e.g., to 600.degree. to no more than 900.degree. F.) to cause the oil and other hydrocarbons to be liberated as a vapor in the evacuated zone. The hydrocarbonaceous solid material advances in proximity with at least one condenser surface so that oil and other hydrocarbons are condensed and recovered from the liberated vapor. The system operates at temperatures which are at all times below 900.degree. F., and generally below 700.degree. F.