Abstract: A cover for a swimming pool. Cables attached to edge area of the cover move within tracks extending along the pool side walls, such that the cover can be moved to a fully opened condition or to a fully closed condition spanning the length of the pool. Electric motors are the preferred mechanism for moving the cables and associated pool cover. The control circuitry for the motors preferably includes a safety device that prevents the cover from being closed against a person or object in the pool. Should the leading edge of the cover strike a person or object in the pool the cover will immediately retract to a fully opened condition.