 As long as armies have moved, tents have served as shelters, headquarters, home, hospital. Tents have a tradition of military service. Extreme portability, lightweight, ease of setup and takedown have been the tent's strong points for centuries. These and the plain fact that no replacement existed. But it is one thing to house and headquarter an army and quite another to hospitalize the wounded. Infantrymen in good physical condition are equal to the hardships of tent life. For a wounded man, the environment is as important as the treatment he receives. Tent hospitals have saved many lives, of course, because they have been available where the wounded were. But they have never been remotely ideal. As a typical hospital environment, this could be in any war zone of the last 150 years, while techniques and technology have advanced at an amazing rate. The only description adequate for the tent hospital is primitive. Sophistication in medical care must equal sophistication in weaponry and tactics. We are a long way from remote control warfare. Men on the ground, at the front, still carry the greatest burden. That is why in 1959, the Surgeon General of the United States Army initiated the search for a new type of mobile hospital. Government and industrial resources were challenged with developing a maximum care hospital that would be self-contained and transportable to any scene of combat or natural disaster. A modern, fully equipped operating room was of prime importance. But every support facility from central material supply to environmentally controlled wards figured in the planning too. The final design was designated must. Medical unit, self-contained, transportable. The system is made up of three basic units outfitted in various ways to provide the many different types of hospitals required. For ease of transportation, each element is its own shipping container designed as part of the package. A C-130 or a larger aircraft can airlift an entire hospital in its containers. Individual units are easily carried by helicopter. Mounted on a removable dolly set, the expandable unit can be towed behind a truck. A utility element can also be transported on a dolly set. One of the multiple shelter units fits the bed of a standard douche and a half. The utility element is the heart of the must system. Electric power, heat, refrigeration, water pressure and heating, compressed air and suction are all generated by the unit. Power and heat come from the unit's turbine engine, capable of running on any liquid fuel available in a combat zone. The expandable shelter is a rigid panel unit. By combining a variety of accessory parts, the shelter can be used as an operating room, laboratory, sterile preparation area, x-ray or similar facility. All interior furnishings can be stored in the central section along with the associated medical supplies. On arrival at a new site, the shelter is ready for use as soon as the sides have been expanded. The interior equipment moved into place and the connections to the utility element secured. The equipment in the operating room is equal to the equipment in any modern surgical suite. All of the latest tools, vital sign monitors, surgical lights, anesthesia and resuscitation equipment, the operating table itself have been developed as part of the must concept. It is now possible to perform complex, delicate surgical procedures anywhere, anytime under any conditions. The third element consists of two parts, the multipurpose shelter and the inflatable shelter. The multipurpose unit is a rigid wall box. It serves to hold the inflatable element during transportation. The multipurpose unit will also hold the specially designed interior modules and medical supplies necessary to outfit the erected inflatable unit. When empty, the container becomes a shelter. Soft insulated sections form walls between the top and bottom doors. Connectors are built in to permit hookup with the utility element. The interior space is adequate for a nurse's station, medical records office or ward supply room. A corridor unit can be used to connect the shelter to the inflatable or expandable units for controlled access. Made of dual walled coated fabric, the inflatable elements are supported by inner tubes between dual layers and reinforced with aluminum bows. Air from the utility element is used to inflate the sections and to maintain pressure. Each section can accommodate 20 beds and related equipment when set up as a ward. Set up time for an experienced crew is about 25 minutes. Must units can be put together in virtually any configuration. A 200 bed combat support hospital or a 400 bed evacuation hospital are equally possible combinations. Detailed plans are available to help commanders select the most economical layout. Entryways and corridors between individual elements maintain a constant environment within the closed loop of the hospital system. Because the environment inside is independent of the climate outside, a must hospital is efficient and effective at virtually any altitude over a wide range of temperatures and the most difficult weather conditions. Once inside a must, the practitioners and the patients are in a medical facility as complete and up to date as any permanent hospital in the military medical chain. The must makes possible a level of patient care that can continue without interruption from front line to state side convalescent ward. By design, the must is flexible, capable of infinite arrangement and rearrangement to fit the ever changing needs of military situations. Evacuation and combat support hospitals of the active army, army reserve and army national guard will soon be converted to must equipment. The first generation of must proves that an alternative to the tent is possible and practical. What lies ahead is not an alternative, but a completely new approach to combat medical care. Modern medicine on the line to serve a modern army.