A security system for protection of a theft-susceptible movable object positioned at a selected location, the security system comprising: a passive magnetic field source that generates a magnetic field; and a monitoring device comprising a magnetic sensor, wherein the monitoring device is further adapted to: take one or more measurements of the magnetic field; detect alteration in the one or more measurements of the magnetic field caused by movement of the movable object; and output an electronic warning signal indicating that the movable object has moved from the selected location; wherein the magnetic field source and the monitoring device are cooperatively configured in one of the following configurations and: the magnetic field source is adapted to be positionally-associated with the movable object, the monitoring device is adapted for placement proximate to the selected location, and the monitoring device being adapted to detect the alteration in the one or more measurements of the magnetic field caused by movement of the magnetic field source relative to the monitoring device when the movable object is moved from the selected location; and the magnetic field source is adapted for placement in proximity to the selected location, the monitoring device being adapted to be positionally-associated with the movable object, and the monitoring device being adapted to detect the alteration in the one or more measurements of the magnetic field caused by movement of the monitoring device relative to the magnetic field source when the movable object is moved from the selected location. a passive magnetic field source that generates a magnetic field; and a monitoring device comprising a magnetic sensor, wherein the monitoring device is further adapted to: take one or more measurements of the magnetic field; detect alteration in the one or more measurements of the magnetic field caused by movement of the movable object; and output an electronic warning signal indicating that the movable object has moved from the selected location; wherein the magnetic field source and the monitoring device are cooperatively configured in one of the following configurations and: the magnetic field source is adapted to be positionally-associated with the movable object, the monitoring device is adapted for placement proximate to the selected location, and the monitoring device being adapted to detect the alteration in the one or more measurements of the magnetic field caused by movement of the magnetic field source relative to the monitoring device when the movable object is moved from the selected location; and the magnetic field source is adapted for placement in proximity to the selected location, the monitoring device being adapted to be positionally-associated with the movable object, and the monitoring device being adapted to detect the alteration in the one or more measurements of the magnetic field caused by movement of the monitoring device relative to the magnetic field source when the movable object is moved from the selected location. the magnetic field source is adapted to be positionally-associated with the movable object, the monitoring device is adapted for placement proximate to the selected location, and the monitoring device being adapted to detect the alteration in the one or more measurements of the magnetic field caused by movement of the magnetic field source relative to the monitoring device when the movable object is moved from the selected location; and the magnetic field source is adapted for placement in proximity to the selected location, the monitoring device being adapted to be positionally-associated with the movable object, and the monitoring device being adapted to detect the alteration in the one or more measurements of the magnetic field caused by movement of the monitoring device relative to the magnetic field source when the movable object is moved from the selected location.