Immersive theatre is a contemporary theatrical form characterized by the dissolution of the traditional separation between performer and spectator, typically employing non-conventional spaces and fostering direct audience engagement. As a research field and academic concept, it investigates the complex interplay of audience agency, spatial design, sensory experience, and affective response within performance environments that challenge established conventions of representation and spectatorship. Its significance lies in illuminating evolving paradigms of performance, exploring the phenomenology of embodied spectatorship, and challenging conventional critical frameworks by foregrounding participation, environment, and the active co-creation of theatrical experience.