Abstract: A device which may serve as a ridge hook for hooking a ladder unto a ridge of a roof includes two wheels mounted upon arms. A threaded rod extends through the hollow core of a ladder rung to secure the device to a ladder. An unhooking arrangement uses a pivot arm, normally biased to be parallel to the ladder, to lift an upper end of the ladder free of the ridge when a control line is pulled. A ladder rung lock is used to prevent relative movement between the upper and lower sections of an extension ladder.