Abstract: Oil shale formations are retorted in-situ and gaseous hydrocarbon products recovered by drilling two or more wells into an oil shale formation underneath the surface of the ground; fracturing a region of said oil shale formation by directing a high energy laser beam into one of said wells and focussing said laser beam onto said region of said oil shale formation from a laser optical system; forcing a compressed gas into said well through which said laser beam was directed at the site of said fracture which supports combustion in the flame front ignited by said laser beam in the fractured region of said oil shale, thereby retorting said oil shale; and recovering gaseous hydrocarbon products which permeate through said fractured oil shale from one of said wells through which the laser beam was not directed.