Merrill’s Marauders is an account of the operations of the 5307th Composite Unit (Provisional) in north Burma from February to May, 1944. The Marauders’ effort was part of a coordinated offensive, the Allied reconquest of north Burma. Details of the offensive are summarized briefly to set the operations of the 5307th within the larger framework. On 10 August 1944 the 5307th was reorganized as the 475th Infantry Regiment. The combat narrative is based mainly on interviews conducted by the historian of the 5307th after the operation and on information furnished the Historical Branch, G-2, War Department, by the Commanding General and several members of the unit. Few records were available because the Marauders restricted their files in order to maintain mobility while they were operating behind the Japanese lines. During the second mission a Japanese artillery shell scored a direct hit on the mule carrying the limited quantity of records and maps kept by the unit headquarters. During the third mission the heavy rains made preservation of papers impossible for more than a day or two. The unit’s intelligence officer was killed at Myitkyina, and his records were washed away before they could be located. This study is the fifth of a series called “American Forces in Action,” designed exclusively for military personnel.