A low-cost retrievable light-weight high-speed thin-kerf reversible electrically-driven core-sampling method and apparatus that is independent of the weight of any drill pipe, drill collars, or any other heavy cylindrical or tubular conduit associated with the coring operation. The flow direction of electric current to the direct-current electric motor of the core-sampling assembly is automatically reversed at frequent intervals so as to cause corresponding reversals in the direction of rotation of its core bit, resulting in the cancellation of any lateral forces on the core bit produced by reactive torque created during the coring operation, since such forces are alternately applied in opposite directions, thus, eliminating any corehole deviation that, otherwise, might occur from the lateral force created by the reactive torque of a down-hole motor that is rotated in just one direction. Geologically-induced lateral forces on the core bit are also minimized because of the light weight and high speed of the reversible electrically-driven core-sampling assembly, which quickly decreases its angle with the vertical, should its trajectory deviate from the vertical.