"Pinned down in a ditch next to the vehicles, they returned the fire with three M-I rifles, two carbines, and a submachine gun. . . . The enemy was using . . . several automatic weapons . . . and after about five minutes . . . began to flank the cars to the left. . . ." These words may seem to have been written by an advance infantry unit or a combat brigade, carrying out an assault against entrenched enemy troops. Instead, this hair-raising narrative comes from the diary of "B" Company of the 1303 Engineer General Service Regiment, a "non-combat" unit attached to Patton's Third Army during his epic pursuit of the retreating German forces across France during August, 1944. Though the 1303 (called "the thirteen-third" by its soldiers) was supposed to perform its duties outside the zone of armed conflict, these men found themselves acting as the southern flank of Patton's rapid advance. More than once, they had to re-build bridges the Germans had hastily destroyed in order to permit the continued advance of American troops--often doing so under enemy fire. Twice they were called upon to deploy as infantry in holding back German attacks. Careful editing and annotation by military historian Joseph C. Firzharris corrects occasional lapses in the diary, clarifies references, and provides important context for following the movements and understanding the importance of Company B, the 1303, and its sister regiments. Patton's Fighting Bridge Builders rewards its readers with a new understanding of both the messiness and the bravery of the Second World War.