Ethology, as conceptualized in 1963 by Niko Tinbergen on the occasion of Konrad Lorenz’s 60th birthday, deals with the function, mechanism, phylogenetic history, and adaptive value of physical traits as well as behaviour Nonverbal signals conveyed by facial expressions, gestures, and body posture of Homo sapiens comprise a large part of communication that most likely exceed the information transmitted because most of nonverbal communication is outside conscious control. Thus from an ethological and evolutionary perspective nonverbal behaviour is much more reliable in terms of the veracity and authenticity of the information that is transported to interacting conspecifics than verbal expressions. In other words, lying nonverbally is much more difficult than it is in verbal communication. This aspect is of utmost importance in clinical therapeutic setting. The ethological methods and procedure to quantify nonverbal behaviour is the ethogram that provides catalogues of discrete elements of the behavioural repertoire of the species under study. Human ethogram have been used in a range of settings, including dyads of mothers and children, psychotherapeutic settings, and other clinical contexts that have greatly advanced our understanding of what kind of information and how it is conveyed beyond insight from subjective evaluations via questionnaires. The purpose of the present workshop is to give an overview of the “state of the art” of the importance of the ethological approach for the understanding of nonverbal communication between human interactions in clinical therapeutic setting. Given our evolutionary history nonverbal behaviour will be explored in nonhuman primates and in animal- human interactions. This aim will be achieved by interdisciplinary discussion between ethologists, primatologists, child psychologists, psychiatrists and psycotherapists.