These nine undated notes from Edison to employee William C. Lang were probably written during the 1920s. They relate to "time cycles" and other matters concerning the management of the laboratory complex. Some of the notes indicate impatience on Edison's part with Langâ€™s abilities. Other individuals mentioned are Edison's personal assistant, William H. Meadowcroft, and two employees named Park and Liebman. The letters were donated to the Thomas A. Edison Papers by Mrs. William C. Lang, Glen Ridge, N.J. Courtesy of Mrs. William C. Lang, Glen Ridge, N.J.