Modern offices are traditionally associated with air-conditioning systems, however in recent times concerns for improving environmental performance in buildings have led to the integration of natural ventilation with the creation of hybrid systems called mixed-mode that allow variations associated with external thermal conditions to improve indoor air quality and people's thermal comfort. This book is based on a research that investigated how people felt about and interacted with a mixed-mode space. Thermal, perceptual and behavioural approaches were used to investigate occupants' thermoregulatory patterns in a multifunctional changeover mixed-mode space. The National Australia Bank (NAB) at 800 Bourke Street, Melbourne Docklands (Australia) represented a unique opportunity for a case study, having nine floors of open-plan air-conditioned offices with the north façade designed as mixed-mode multifunctional kitchen-lounges at every floor where people can choose between air-conditioning and natural ventilation. The case study was used as a basis of investigating the indoor environment and its occupants through field work and the adaptive thermal comfort theory.