In this PhD thesis, I present five studies on white-collar workers’ unscheduled interaction in open office environments, the results of 50 days ethnographic fieldwork in seven Danish case organizations. Each study is featured in independent research papers that respectably seek to answer the following questions: What spatial and social factors occasion white-collar workers’ conversational encounters? (paper 1), how do conversational participants establish mutual gaze in four-person desk clusters? (paper 2), how do recruiters with on-screen difficulties achieve a side-by- side spatial orientation toward their screen with an assisting recruit? (paper 3), what are the features that make side-by-side F-formations preferred for co-editing digital texts? (paper 4), and what entitles co-workers to join conversational gatherings at the coffee machine? (paper 5). The presented studies draw on fieldnotes and photographs from my shadowing of 15 white-collar workers as well as audio- visual recordings of everyday life in open office environments. Through a multimodal analysis of the video data and detailed ethnographic accounts, several key findings emerge: The direct visual and audible access between co-workers at open desk clusters and pathways is found to occasion “coincidental desk conversation”, “neighbor conversation” and “timed desk conversation”. Furthermore, “ad hoc meeting conversation” as well as “pre- and post-ad hoc meeting conversation” is occasioned by the involved co-workers’ agreement to interact, (paper 1). Vis-à-vis seated co- workers create a momentarily spatial condition for gaze in interaction by applying a variety of practices whereby stationary computer screens are bypassed. Different bypassing practices are afforded by the interrelation between two bodily-material factors in the form of the coworkers’ work gaze and their computer screens’ dimensions, (paper 2). Recruited co-workers (recruits) are made to abandon their desk through requests and pre-questions, and recruits orient to recruiters’ involvement with work activity-relevant objects, which is treated as a visible, bodily indicator of urgency that has implications for the timely occurrence of recruits abandoning their desks, (paper 3). Side-by-side co- workers rely on the interplay between available physical and digital resources to achieve “phygital” highlighting as a social recognizable action that is necessary for the accomplishment of joint attention and co-editing actions, (paper 4). Eight sources of entitlements enable white-collar workers to join coffee machine conversations: institutional membership, shared space, physical attractors, alibi- objects, embodied invitation, preceding presence, summons or direct verbal address, invitation via updating topicalization, (paper 5). Based on these observations and findings the PhD thesis demonstrates how open desk and cafe area interaction is a social-material-spatial phenomenon.