The models, schemas, recipes and mantras, which leaders of change bring to the projects they manage, are relatively little understood. Here the nature of these structures is explored from the perspective of mental model theory. The positive potential of simplified representations of business problems is contrasted with the negative value of certain long-cherished and counterproductive recipes for action. It is suggested that many managers, when initially questioned about the nature of the cognitive structures they bring to their work, tend to make excessive claims for the stability and internal consistency of their personal repertoire of available material. The popular distinction between tacit models, as “undiscussable and indescribable” phenomena (Argyris and Schön 1996), is compared with a more dialogic view of managers as men and women subject to frequent changes of stance as they engage with significant colleagues. Simple links between personality types or cognitive style and mental models in use are challenged and it is suggested that a leader’s repertoire of models and heuristics is often extended well beyond the zones of comfort that may be inferred from personality theory. Management and cognitive competences are advocated as potential limiters of models in use and facilitators of change. Classification of the mental models of leaders is attempted in order to illustrate the value that individual models may have as narrational, ego-defensive, processual and discursive material. The depth, superficiality and motivation behind certain models are discussed, as is the question of how easily leaders of change can adapt these different types of structure as a result of the feedback they get from the success or failure of their projects. This paper forms part of an ongoing study of senior managers who are leading organizational change in the public and private sectors.