If I can summarize the aim of this book in one sentence, it is to expand the possibilities for computer-mediated communications interfaces in interpersonal communications. The book explores what an “interface” means in terms of technology and what is needed for an interface to support how people relate to each other. The focus is on the tacit dimension of interpersonal communication, including nonverbal communication acts between people working on a common task, the nature of learning in expert-apprentice encounters in the expressive arts (dance, music, and so on) and professional training situations, and collaborative work in the arts and professions.

A significant concern of this monograph is the transfer of tacit knowledge, meaning that knowledge that is not represented in propositional form, but consists of “knowing how” rather than “knowing what.” Tacit knowledge is often regarded as synonymous with embodied knowledge, including skills, experiences, and ideas in the mind of an expert, who can use the sum of this expertise without applying an explicit rule or invoking an explicit principle. Being difficult to reduce to writing, tacit knowledge is generally learned by experience or transferred in the context of interpersonal encounters in teacher-student or collaborative work conditions.

The book begins with a survey of philosophical and conceptual foundations, including the nature of interaction, interfaces, presence, mediation, and dialogue, and summaries of discourses on the nature of knowledge and knowing from the ancient Greek philosophers, early modern philosophy, and modern thinkers from the early to mid-20th century and after. It then elaborates on tacit or embodied knowledge, discussing the nature of expertise and communication. This is followed by an exploration of mediation and communication by nonverbal means, in particular physical actions in a shared space, as contrasted to participants who are physically separated and either unable to observe one another or severely restricted in such observation. A final chapter discusses a selection of research projects by several different research groups and synthesizes the ideas addressed in the previous chapters and the experimental frameworks into a unified frame of reference. It closes with the proposition that a well-designed mediatory interface should facilitate tacit engagement, in other words, allow human participants to interact in ways that facilitate collective moments and allow the tacit transfer of knowledge.

This monograph offers insights, frameworks, and research summaries, rather than prescriptions and solutions. It is apparently written mainly for an academic audience, especially researchers and graduate students in human-computer interaction (HCI) and related fields. That said, it may also be of interest as background reading for professionals in areas where HCI and computer interfaces play important roles, such as navigation, manufacturing, and operations control systems, and perhaps especially in the context of developing training systems for these.