This article traces the historical evolution of the memorandum as a genre of written communicationin American business during the late nineteenth and early twentieth centuries. It draws
on published and unpublished materials from the period, including archival materials
from E. I. du Pont de Nemours and Company and Scovill Manufacturing Company. The
historical analysis shows that the memo developed from the letter, not for reasons related to
rhetorical theory, but as a practical response to two sets of developments: (I) the emergence
of new managerial theory and techniques, and (2) innovations in the technology of written
communication. The study also reveals a significant lag between the actual emergence of the
genre and its recognition in instructional materials in communication.