Nelson C. Baker was a lieutenant working as an executive officer to Captain Palmer in the Second Provisional Special Engineer Detachment at Los Alamos. Prior to his work on the Manhattan Project, Baker spent two years in Italy in the 16th Armored Engineer Battalion of the 1st Armored Division in North Africa and Italy. When he returned to the United States in the summer of 1944, Baker met with General Leslie R. Groves, and was reassigned in August. Despite the secrecy surrounding his assignment, Baker made the grueling trip to Los Alamos, arriving on August 14th, 1944. Baker started off as an executive officer but eventually took on the titles of Personnel Officer, Supply Officer, and Post Recreation Officer as well. These positions encompassed a variety of duties, including training military personel, overseeing office staff working on scientific research, doing the payroll and paying the troops, as well as censoring letters.
In October of 1945 Baker left Los Alamos, but continued to serve in the military until 1961, retiring with the rank of Lieutenant Colonel. Baker also worked as a personnel and security investigator for the U.S. Civil Service Commission and the Office of Personnel Management until July 1982 when officially retired.