Human conversational partners are able, at least to a certain extent, to detect the speaker's or listener's emotional state and may attempt to respond to it accordingly. When instead one of the interlocutors is a computer a number of questions arise, such as the following: To what extent are dialogue systems able to simulate such behaviors? Can we learn the mechanisms of emotional be- viors from observing and analyzing the behavior of human speakers? How can emotionsbeautomaticallyrecognizedfromauser'smimics, gesturesandspeech? What possibilities does a dialogue system have to express...