Indoor spaces have not traditionally been considered the domain of human ecology. They have been the subject of cultural, architectural, and sociological inquiry, and more recently the site at which various pathogenic or toxic encounters may be studied; yet, these concerns have rarely been investigated as part of one unified and codependent ecology. This special issue aims to remedy this dislocation by beginning a conversation between a range of disciplinary perspectives concerned with the indoors. This ambition is not only linked to a desire to articulate and connect multiple interacting variables operative in indoor spaces, but also to address both a number of factors that are increasingly creating indoor environmental conditions that are suboptimal for human habitation, and the broader more-thanhuman ecosystems in which they are situated. Although certainly not exhaustive in scope, the research presented in this special issue provides an exemplary profile of situated knowledge that must form the basis of future, integrative, transdisciplinary research into indoor ecologies. Spanning design, architecture, social and human ecology, environmental psychology, sociology, mycology, biotechnology, spatial sciences, statistics, engineering, philosophy, and "lay" and experiential knowledge perspectives, this special issue uncovers a number of the challenges and fertile points of overlap across epistemological approaches and areas of concern within the indoors. The goal of this issue is to highlight the points of divergence, and, more crucially, the points of convergence from which a new transdisciplinary approach to indoor research can emerge.