This study explores Command and Control in the context of emergency management in the United Kingdom (UK) and the United States of America (US). Command and Control is regarded as both the dominant and traditional model of emergency management though debate continues as to its appropriateness in the face of disaster. Criticism is perhaps strongest within the academic community. Concerns include it being overly bureaucratic and centralised, inflexible and slow for decision-making, though for some it brings order to chaos and is thus essential. The model is embedded in legislation, policy and practice. The Police, Fire and Ambulance services, and others, are brought together within frameworks such as the UK Gold, Silver and Bronze (GSB) and US Incident Command System (ICS) to collectively respond when disaster strikes. However, "interoperability" problems, whereby organisations are seemingly unable to work together occur compromising response efficacy and the failings during Hurricane Katrina (2005) stand as testament to this. This thesis examines how emergency responders interpret Command and Control, and the implications of this for interoperability. This mixed methods interpretive study comprises 30 semi-structured interviews with key UK and US emergency management practitioners focusing on their views of Command and Control. Participating organisations include Police, Fire and Ambulance services, and Local and Central Government agencies. The research design embraces linguistic and visual metaphor to answer the Central Research Question "how do U.K. and U.S. emergency management practitioners metaphorically interpret Command and Control?" The collated data were analysed using content analysis to identify general themes. Then, Morgan's (2007) 8 seminal organisational metaphors and Lakoff, Espenson and Schwartz's (1991) Master Metaphor List (MML) were employed to identify metaphors used to communicate understanding of Command and Control in both the linguistic and visual domains. The findings show that interpretations of Command and Control are varied, suggesting that key organisations at the heart of emergency management are not "on the same page". However, some commonality based around Morgan's Brain, Culture and Machine metaphors was noted. Over 500 linguistic metaphor types were found providing an insight to the rich natural language of emergency management. The use of MML metaphors such as Status is Position; Progress is Forward Motion and general metaphors such as Natural World and Cooking were frequently noted meaning they are broadly understood within a multi-agency setting. Consequently, the use of such terms enhances interoperability as they can increase the likelihood of shared understanding. Thus, establishing a new theoretical domain and the basis for a metaphorical language of emergency management. Furthermore, 30 visual metaphors (diagrams) were collated that demonstrated some variability in perspective. However, a standardised interpretation, 27 of 30 or 90% of the sample-frame, based on the Status is Position metaphor linked to a hierarchical top-down frame associated with the traditional model was noted. This indicated a heavily embedded view, which contrasted the more variable linguistic findings. Building on these results, a suite of learning tools were constructed; the Command and Control Interoperability Tool Box or CCIT-Box. This contains 2 interoperability assessment tools, a Theory of Interoperability Metaphors (TIM), and 5 conceptual metaphors, namely Command and Control as a Candle, a Trivial Pursuit Pie, a Golden Thread, Spinning Plates and a Virus and Antidote. These tools have been validated through use in academic and professional settings. Their design opens up the "mind's eye" by harnessing the power of metaphor in an innovative and novel way using linguistic and visual methodology. The tools engage participant's in deeper and more critical review of their own and other's views of Command and Control, and indeed broader emergency management issues. This mechanism effectively bridges the known gap between academic theory and practice to enhance interoperability and knowledge to (ideally) reduce the loss of life and suffering in future disasters.