Paul Ekman’s research on facial expression and body movement began in 1954, as the subject of his Master’s thesis in 1955 and his first publication in 1957. In his early work, his approach to nonverbal behavior showed his training in personality. Over the next decade, a social psychological and cross-cultural emphasis characterized his work, with a growing interest in an evolutionary and semiotic frame of reference. In addition to his basic research on emotion and its expression, he has, for the last thirty years, also been studying deceit.