Mary Ann Horton (formerly Mark R. Horton) is a computer scientist and transgender educator and activist. Horton invented uuencode which was the forerunner to e-mail attachments. As a graduate student at U.C. Berkeley, Horton also contributed to BSD, working on programs such as vi, terminfo, curses, and the B News Usenet reader. She would later continue this work at Bell Labs, and while there, also lead the growth of the Usenet network throughout the 1980’s.