This handbook examines the important relationship between interior environments and their users, presenting diverse analyses of human-centred design approaches. It encompasses empirical research across multiple dimensions - from the various scales at which interior spaces are experienced to cultural influences, theoretical frameworks, health impacts, and educational methodologies. Interior architecture has evolved significantly, establishing itself as a rigorous and crucial academic discipline and profession in global society. Rectifying outdated perceptions of designed interiors as merely a decorative realm, this handbook - featuring contributions from international authors - highlights the profound social, cultural, technological, and ecological impacts of interior architecture in the 21st century. The handbook presents cutting-edge research that emphasises technological advancements in interior design processes, comprehensive analyses of human-centred design through empirical studies and intellectual on spatial experience at various scales, cultural context and influences, theoretical perspectives and frameworks, health and well-being considerations, and educational approaches and professional practices. The volume is relevant to academics, design researchers, practitioners, and students by exploring interior architecture through multiple disciplinary lenses: psychology, sociology, neuroscience, anthropology, and ecology. Readers will gain valuable insights into how analytical approaches to interior architecture contribute significantly to positive human experiences and conditions in our built environments.