Then, a young American sentry stopped the pair. He was friendly enough, but firm: they must explain where they were going and why. The Frenchmen replied as well as they could until, all at once, they stiffened and fell silent, their eyes wide in astonishment. For over the sentry's shoulder they saw four GIs in muddy battle jackets and dull green helmets walk over to a monstrous tank and, with one man at each corner, simply pick it up, turn it around and set it down again. Thus, or so the story goes at any rate, was the cover of the 603rd Engineer Camouflage Battalion broken and the security of a neighboring armored division imperiled at a critical moment in the Allied offensive. Fortunately, no damage was done.

The 603rd was one of four units that formed what was perhaps the most enigmatic outfit ever fielded in battle, a group called the 23rd Headquarters Special Troops. The 23rd's troops were "special," all right. They specialized in impersonating other troops. The war with Germany came to a close 40 years ago this mouth. For 268 days in mid-1944 and early l945, the 23rd's 82 officers and 1.023 enlisted men pretended. at one time or another, to be the 5th Armored Division, the 4th Infantry Division, the 6th Armored Division, the 90th Infantry Division and many other Army outfits hard at work in the hedgerows and forests of northern Europe. With inflatable rubber guns and vehicles, with ever-changing shoulder patches, stencils to make phony signs, and with amplified recordings of heavy equipment in action, the 23rd played role alter role. Its men fired only a few shots in anger, but plenty for the sake of theatrics.

The purpose of all of that razzle-dazzle was to fool the enemy and, by doing so, enable the troops that the 23rd was impersonating to sneak into new positions, to launch a surprise attack or in some other way to catch the other side off guard. Sebastian Messina, a radioman with the 23rd from Worcester, Massachusetts likened his unit's modus operandi to the old football Statue of Liberty play, with variations. "Suppose the Umpteenth Division is holding a certain sector," he told a newspaperman after the war. "Well, we move in, secretly of course, and they move out, We then faithfully ape the Umpteenth in everything the Germans were accustomed to seeing them do or have, assume their identity totally. Then the Umpteenth, which the Boches think is in front of them, is suddenly kicking them in the pants ten miles to their rear." Deception was used as a military tactic long before the Greeks slipped their wooden horse into Troy, but it didn't really come into its own, in a systematic and organized way until World War II. The advent of sophisticated reconnaissance and intelligence techniques, together with unprecedented battlefield mobility, put a new premium on the possibilities of tactical spoofing. Field Marshal Bernard Montgomery pulled off an elaborate hoax in the British Eighth Army's decisive victory over Erwin Rommel's Afrikan Korps at El Alamein in North Africa, and the United States deftly faked out Germany's intelligence experts prior to the Battle of Tunisia, The success of those exercises in camouflage and cover plans he1ped convince American strategists of the need for a chameleon like ghost army in the European theater. Early in 1944, therefore, the War Department authorized the formation of just such an outfit, the 23rd.

Three units were hurriedly assembled front around the country for training and reorientation at Camp Forest in Tennessee. The mission of the 23rd's Signal Company was to develop and employ radio counter intelligence tricks. The 406th Engineer Combat Company, a disciplined fighting unit trained in desert warfare, was put in charge of all around security and tough construction jobs. The aforementioned 603rd Engineer Camouflage Battalion had already been experimenting with deceptive installations for nearly two years. It was given the responsibility for camouflage and dummy equipment. Yet another outfit, the 3132nd Signal Service Company, was trained separately at the Army Experimental Station in Pine Camp, New York, where it pioneered in the development of "sonic deception" techniques.

The 603rd epitomized the creative character of the 23rd. It was composed largely of artistic types who had been recruited from New York, Philadelphia and Chicago. Some of them had known each other while attending various colleges and universities, and such prestigious art and design schools as the Pratt Institute, Cooper Union and the Art Institute of Chicago. The average IQ of the 603rd was 119, rumored to be the highest in the Army.

Many of the 603rd's recruits were destined to achieve fame and success after the war was over. There was a young fellow named Bill Blass, for example, who wanted to set himself up as a fashion designer some day. Others included Ellsworth Kelly, artist and an originator of the "hard edge" painting, whose work now hangs in the Museum of Modern Art: George Diestel, who became a famous Hollywood set designer; Art Kane, a well known photographer: Arthur Singer, one of the country's most respected bird painters; and Arthur Shilstone, a distinguished illustrator whose work, appropriately enough, adorns this article. Still others became influential university professors, industrial designers and creative directors or i1lustrators with advertising agencies.

Notwithstanding their artistic temperaments, the men of the 603rd were required to endure the torment and boredom of training, marching, drilling and KP duty like any other GIs. It was not a burden always nobly borne. One battalion mess sergeant gained notoriety for making KPs clean his filthy grease pits. "I want to be able to see my face in there!" he would bellow. I guess there's no accounting for taste," an artist soldier snapped back one day. "You just got yourself a whole week of KP," the sergeant roared. Sometimes it all seemed a bit like Beetle Bailey.

For nearly two years, the 603rd was stationed at Fort Meade in Maryland, where it was required to do the same drills over and over, fixing camouflage nets and painting camouflage on trucks an artistic accomplishment, Shilstone recalls, that "any chimpanzee could have done as well." As time dragged on the men began to lose hope of ever leaving. "The 603rd will never go overseas," they repeated to each other so often that the phrase almost began to take on the significance of a unit watchword.

Gradually, the distinctions between the artists and the others began to blur. They all groused together, drank together and brawled together. But the differences never did vanish completely. A few of the troops filled their off hours sketching. One man kept a Stradivari violin in his barracks. A young dress designer, rich and spoiled, sat on his bunk eating chocolates and endlessly writing letters. One night long after taps, the stillness of the 603rd barracks was broken by the sound of low voices engaged in muffled but earnest conversation. "And there we were at Toots Shor's," one man whispered, "when, Mother came in wearing this blue sequin dress…"

When the 603rd, sketchbooks and all, finally pulled up stakes at Fort Meade and arrived at Camp Forrest in January 1944, it was met by Colonel Harry Reeder, a savvy career man, Reeder had studied at a service school in Paris and commanded a crack armored infantry regiment. Nothing in his experience had prepared him for his assignment as bead of the 23rd. In a wonderfully engaging official history of the unit, Frederic Fox, who was a captain in the Signal Company, recalls the scene this way: "Since no one knew how a deception unit was supposed to operate, the training program was not easy to write. Officers, who had once commanded 32-ton tanks, felt frustrated and helpless with a battalion of rubber M4s, 95 pounds fully inflated. The adjustment from Man-of-action to man-of-wile was most difficult."

Difficult or not, the adjustment had to be made. The men practiced setting off flash devices, canisters with small charges triggered by electricity, to simulate artillery barrages. They considered how to achieve large-scale deception using their radio equipment. They learned how to deploy their dummy vehicles and artillery weapons, which were inflated with small motor-operated compressors. The signal service unit training up in New York worked on its own unusual repertoire: amplified recordings of tanks, half-tracks and jeeps that would be used at night to fool the Germans into thinking that entire armored divisions were on the move.

Then, one night in early May, the main body of the U.S. Army's first and only tactical warfare deception unit trooped aboard the USS Henry Gibbons in New York harbor and embarked for Great Britain. There, the 23rd bivouacked for a month in six-man tents on the elegant grounds of a Victorian manor near Stratford-on-Avon. The British called the place Walton HaIl; the GIs called it Mouldy Manor. "Training by all units was continued," Fox notes in his chronicle, "with considerable emphasis on athletics and recreation." Parties were held. Some of the men attended Shakespearean productions at Stratford; others passed the time relaxing at the Leamington Spa.

After about half of the command had departed for France, the remainder, some 600 men, spent a week waiting their turn at Charborough Park, the rambling estate of Adm. Lord Reginald Ernst-Ernie Drax, KCB, DSO. Often, while the enlisted men watched deer and played baseball on the manicured lawns, the Admiral invited the officers in to enjoy a glass of port and a warm bath. Everything went swimmingly until the day before the men pulled out, when their chagrined host announced haughtily: "Someone has beeeen in my sherry!"

It took two months, two planes and nine ships to transport the entire unit to France. The first detachments hit the beach shortly after D-Day and four men were wounded. Victor Dowd, a platoon sergeant with the 603rd and now an illustrator living in Connecticut, touched down with his platoon on Omaha Beach in a C-47 transport plane at D-Day plus seven. He wondered why there were nurses on the plane and then he saw the wounded waiting on the beach. Not long after that, the reality of warfare came home to John Hapgood, who was a corporal with the 603rd and is now an artist in New York City, when he took cover under a railroad car with fellow artist Phil Hornthal. German shells were crashing all around them. Between explosions, one of the men shouted sardonically, "The 603rd will never go overseas!"

The 23rd's acting debut, Operation Elephant, was greeted with mixed reviews. It took place in the forest near Cerisv-la-Foret, France, in early July and involved about 400 men who were assigned the task of simulating combat elements of the 2nd Armored Division while that unit secretly took up a new position. German units were maintaining a defensive position nearby. As the armored division moved out, the 23rd moved in, replacing real tanks with dummies and substituting rubber artillery for steel weapons.

Did it work? An official digest of the 23rd's operations concludes that the deception was effective because the Germans, expecting an attack in the vicinity where the 23rd was operating, held their position while the U.S. tanks made their move. However, historian Fox suspects that "little good was done." The main problem had to do with the fact that the 2nd Armored Division carried out its move in broad daylight with no attempt at secrecy. The need for better liaison and stricter camouflage measures, borrowed shoulder patches, simulated supply dumps, and cover stories concocted for consumption by enemy collaborators was assiduously observed from then on. It wasn't long, in fact, before the 23rd had a voluminous file on visual identifications and the men suffered many a bloody finger sewing bogus shoulder patches on their uniforms before going into action.

In Operation Brest, which took place outside the great French port city in late August the 23rd put on a terrific show. Its principal objective was to bluff the Germans into surrendering the city. The 23rd was supposed to impersonate two tank battalions and a field artillery battalion. This it did, augmenting real units already in place with "troops," using dummies, spoof radio installations and a variety of misleading special effects. The 23rd kept up a pretense of routine firing by setting off its flash canisters; as was often the case in subsequent operations, a few authentic weapons remained in place to add substance to the sham.

On three successive nights, men of the 23rd approached within 500 yards of the enemy lines and projected their amplified recordings of tanks approaching, taking up positions and withdrawing. Engines roared. Gears clashed and ground. Voices shouted in the dark, orders, counter orders, frustrated cursing at yet another Army snafu. Friendly troops a mile away were completely fooled and so, apparently, was the enemy. The dummy flash batteries drew repeated counter fire and the German Commander at Brest, General Herman B. von Ramcke, later testified that he had been taken in by the armored act. Von Ramcke, with a force of approximately 38,000 men, 17,000 more than U.S. intelligence estimated, had already made a decision to stand and fight. But even though Brest did not fall until mid-September, the 23rd's theatrics were successful.

The American offensive began to bog down, but in eastern France the 23rd kept on the move. Its men enjoyed onion soup and Cointreau in Torcy, uncovered an immense German cache of cognac in Les Garangers and bought perfume in Paris. In southern Luxembourg, they assumed the guise of an armored division and managed to checkmate a duped German infantry division for seven days. In Belgium, the 23rd realistically simulated still another U.S. outfit ostensibly lolling about at a rest camp. The unit supported a "river-crossing demonstration" near Uckange, France, facilitating a surprise crossing of the Moselle elsewhere by the U.S. 90th Infantry Division. After the German breakout in early December, the Great Deceivers used their bag of tricks to help cover the movement of an infantry division into the Bulge.

As Sebastian Messina pointed out, much of the 23rd's energy was devoted to obscuring the movement of other troops. In a typical cover operation, the 23rd's actors stayed in plain sight in the area they were supposed to be holding. They kept fires burning at night and visited supply dumps regularly. Having been briefed on the recent history of the outfit they were "playing," they chatted with civilians about things anyone in the real unit would know. Arthur Shilstone clearly recalls riding around villages in trucks for hours. At the rear, the two outside men would wear the proper patches and no one could see whether the rest of the truck's complement of 12 was inside the canopy or not.

When impersonating an armored unit, the 23rd often-used half-tracks to scar the ground with tread marks like those of tanks. Then the rubber tanks would appear, partly hidden by netting and sometimes augmented by a real tank or two. The dummies were always inflated at night, which took about half an hour using the compressor pumps. As the air entered, they would squirms like sulphur snakes.

There were problems, of course. Since the dummy equipment was positioned in the dark, an inflated tank would sometime be discovered in the morning facing the wrong way, a dead giveaway to aerial reconnaissance. (That's why those two French cyclists saw a tank being picked up and turned around.) The morning sun could cause trouble, too. One day some rubber planes began collapsing with a series of loud reports because the sun heated air had expanded. There was trouble with leaks, too. The troops dreaded the sight of limp gun barrels at first light, when the German reconnaissance planes usually flew over.

It was difficult to gauge the effects of the 23rd's operations. There were times when they appeared to have no impact whatsoever. There were other times when they confused friend more than foe. Often enough, though, the Germans were completely hoodwinked. Prisoners spoke in awed terms of an "elusive" division. A map overlay captured before one engagement showed that the enemy had mistakenly positioned a U.S. unit right where the 23rd wanted them to think it was. Even Axis Sally, the notorious German radio propagandist, was taken in by that ploy. Given its flair for the dramatic, it was perhaps inevitable that the 23rd's most impressive battlefield performance would be its last. In March, the United States crossed the Rhine at Remagen, but the Ninth Army was held up near the river at Viersen, not far from the Dutch border. One of the Ninth's three corps moved north under the cover of darkness and prepared, in absolute secrecy, for a real assault on the Rhine. The 23rd teamed up with the Ninth's other two corps to engage in a bogus buildup designed to convince the enemy that a crossing would be attempted near Viersen in April. Engineers built facilities and paraded about with bridging equipment. Medical installations were set up and a vehicle control center broadcast news of heavy traffic. The 23rd's "notional divisions" made a brazen show of themselves around Viersen. Each one had nearly 400 rubber vehicles, including five liaison planes, and aerial photos of their installations looked remarkably authentic. All of the 23rd's sonic tricks and special effects were brought into full play.

It was a show that would have warmed the cockles of Cecil B. DeMille's heart, and it worked. The real Rhine crossing in March came as a complete surprise to the Germans and many American 1ives were saved. For its efforts, the 23rd received the next best thing to an Oscar, a formal commendation for "careful planning, minute attention to detail, and diligent execution" from the Ninth Army's commander.

The 23rd was inactivated in September 1945. Unlike many returning soldiers, whose exp1oits have been emblazoned across the pages of the nation's newspapers, the men of the 23rd came discover that Americans didn't know any more about them than the Germans did. The reason: everything they'd done had been classified "top secret." But at least, to the inevitable question, "What did you do in the war, Dad?" veterans of the ghost army could honestly respond: "I blew up tanks and guns, Son."