Face-to-face dialogue is the basic and universal form of language use, from everyday life to professional interactions. This book, written for a range of readers from researchers to practitioners, presents a program of research into the key features that make face-to-face dialogue unique: First, interacting in dialogue is highly reciprocal, with constant moment-by-moment interchanges. Dialogues that are face-to-face are also multimodal, combining speech with hand and facial gestures (including gaze) that contribute to both the content and the coordination of a dialogue. The book starts with two essential changes of focus, from individuals to interactions and from nonverbal communication to co-speech gestures. These lead to a wide variety of video-based experiments into how dialogue works, always from an interactional rather than an individual perspective. Results include the influence of the listener on the speaker, the importance of co-speech gestures in the coordination and management of dialogue, and an empirically supported model of mutual understanding as a constant, three-step micro-process of co-construction. Finally, there are applications to dialogues in a variety of practical settings, including psychotherapy, computer-mediated communication, infant autism, and medical consultations. Because microanalysis of even the most ordinary face-to-face dialogue reveals precision and skill on a second-by-second level, virtually every study includes examples from actual dialogues, and a supplementary website provides video analysis of these examples, which brings the details of face-to-face dialogue to life.