This folder consists primarily of postcards and other correspondence from members and former members of the Muckers of the Edison Laboratory. Included are letters by James B. Ballantine and Nils Traaholt, written at the ore milling plant in the Dunderland region of Norway, where both men were working in 1905. Other items include bills for dinners, humorous sketches by A. Theo E. Wangemann, and various versions of the organization's constitution.

Eight letters from members or former members have been selected. A copy of the Muckers' constitution can be found in the "1906. Edison, T.A. - Employment" folder in the Document File Series.