Set of four 29.75x40" posters printed by US Government Printing Office as part of a Division of Information - Office for Emergency Management series in 1941. Until the attack on Pearl Harbor, America's involvement in World War II consisted of a ramped-up industrial production of war material for the embattled Allied nations. Congress passed the Lend-Lease Act on March 11, 1941 and although not a military act, it eliminated the possibility that America would remain neutral during the conflict. These exceptional, patriotic work incentive posters were issued by the Office of Emergency Management right on the cusp of America's entry into the war. They were equally as efficient during the few official months of Lend-Lease as they were after America's official declaration of war. Each was designed by Leo Lionni (1910-1999), who, along w/Herbert Matter, Lester Beall and Milton Ackoff, carried photographic poster illustration to new heights of inventiveness. War preparedness required the quickest, largest build-up in history, triggering numerous production incentive posters, these four being among the best. Each used the same layout - the American flag's blue field contained a photograph of Homefront workers, the product of their labor being shown on the warfront, amid red/white stripes. Each features same "Keep 'Em Rolling!" slogan. Each has been rolled. First poster shows welder at work in blue field w/four duplicate photo images of light American tank on red/white stripes. Scattered handling wear along left/right margins w/considerably heavier wear at upper left. .5" tear at top center. VG/Fine overall, but margin issues could be easily matted out for framing. Second poster shows man working on propeller unit of plane in blue field w/four duplicate photo images of US Army Air Corp warplane on red/white stripes. Left margin has small area of faint staining at bottom left. Right margin shows moderate wear including areas of insect damage resulting in a number of small holes. VG/Fine overall, but margin issues could be easily matted out for framing. Third poster shows group of welders in blue field w/four duplicate photo images of PT boat on red/white stripes. 2" corner crease at upper right and right margin shows moderate wear including insect damage that has resulted in a number of small holes. VG/Fine overall, but margin issues could be easily matted out for framing. Last poster shows engineer w/instruments in blue field w/four duplicate photo images of artillery battery in red/white stripes. Poster shows moderate to heavy insect damage on reverse and at margins w/several small margin holes. Poster also has some scattered insect holes across poster (mostly affecting top 10" or so) and top left corner is missing 2.25x2.5" piece. Right margin also shows wear at top, w/.25" and .5" tears. Good/VG. Rarely offered as a complete set, and this is the first such example we've offered in our 49 years. One of the most important and early World War II poster sets produced. Campbell Family Collection.