A passive/reactive device protects a Payload from injury or damage due to the shock caused by impact or explosion. When the vehicle or structure mounting the Payload receives a shock pulse, the invention limits the acceleration transmitted from the vehicle or structure to the Payload to an acceptably low, user-adjustable level which is substantially constant or is some other user-adjustable force-displacement function. The invention is capable of doing so even when the peak magnitude of the imposed shock is on the order of thousands of G's, with a rise time to peak on the order of microseconds. The invention can be embodied to operate passively, without any external source of power, sensor system, or CPU, although they can be added to improve certain usability features. The invention also absorbs or dissipates the shock energy in substantially the minimum distance possible without exceeding the user-defined acceleration limit on the Payload. The invention can also react when a shock-producing impact is imminent by repositioning the Payload away from the impact site. The Payload can be a person or persons, or shock-vulnerable equipment. The shock can be created in a number of ways, including an explosion, an impact or collision, the slamming on high-performance boats and some off-road vehicles, earthquake, or even intentional shocks on an amusement thrill ride. The ability of the invention to protect against shock is limited only by its ability to absorb or dissipate the energy of the shock pulse on the Payload. The device can be implemented to protect against shock from any arbitrary direction. The name Shock-Limiting Interface, Compact (SLIC) is coined for this invention.