Lester Donald Earnest (born December 17, 1930) is a United States computer scientist. He began his career as a computer programmer in 1954 during a stint as a U.S. Navy Aviation Electronics Officer & Digital Computer Project Officer at Naval Air Development Center, Johnsville, Pennsylvania. In 1956 Les joined the Massachusetts Institute of Technology to help design the Semi-Automatic Ground Environment (SAGE) air defense system.
Starting in 1959 the focus of his career shifted to innovations within the field of word processing. During this time he was responsible for developing the "first pen-based computer system that reliably recognized cursive writing" and the first spell checker.
In the late 1960s Les continued to diversify the types of technologies he involved himself with. He made significant contributions in the fields of robotics through the creation of systems that coupled computer vision with prosthetic and vehicular applications.
In 1965, Les became Executive officer at Stanford Artificial Intelligence Laboratory, and he soon became deeply involved with the Advanced Research Projects Agency Network (ARPAnet) startup committee. This association would lead him to the one innovation he has received the most acclaim for: The invention of the Finger protocol (RFC 742) in the early 1970s.
Accomplishments in computing aside, Les is also a long-time bicycle enthusiast. He has served as director and/or officer in several prominent cycling associations including the U.S. Cycling Federation, the U.S. Bicycling Hall of Fame, and the Federation of Independent Associations for Cycling.