Abstract: Oil shale is retorted, preferably in situ, by passing velocity flow of super-heated air through one or more conduit-like passages in direct contact with exposed surfaces of oil shale. Kerogen pyrolysis products are recovered by condensation of the vapors and collection of the condensate and by collection of the gases and separation of the valuable gases from the normally waste gases. Some of the waste gases may be recycled with the air for controlling combustion of the kerogen content of the shale.