Abstract: An in situ retorting method and system for recovering hydrocarbons from an oil shale deposit. A retorting zone is formed in the deposit and is comprised of at least two galleries which are separated by a barrier of oil shale thick enough to prevent leakage of gas between galleries. A plurality of rooms are formed within each gallery and are defined by walls of oil shale having substantially less thickness than said barriers. As a gallery is completed, it is sealed and rubblized oil shale within the rooms of said gallery is retorted and the products recovered. Since the barriers between galleries protect workers against gas from a retorting gallery, work can continue on adjoining galleries while said gallery is being retorted.