Abstract. The paper discusses how the concept of resilience has improvisation as a key premise. The paper aims to map out where aspects of improvisation are inherently part of resilience. The results are discussed in terms of possible organizational consequences in high risk environments. Three different approaches are applied; First; how resilience and improvisation are related in general. Second; improvisation in resilient adaptation, in which sensemaking plays a key part. Third; recasting resilience and improvisation onto the Cynefin framework for making sense of complex systems and organizations. The paper integrates the three approaches to resilience and improvisation, and outlines what types of initiatives it may be relevant for organizations to take with respect to design, work organization and training to facilitate successful improvisation. By suggesting improvisation as an engine of resilience, it follows by implication that resilience as such does not preclude the possibility of inadequate improvisation. Hence, the potential for serious safety breaches remains, regardless how resilient we may be.

p.2 it could be argued that all operational activities should be considered from a non-routine perspective.

p.2 Improvisation is characterised by nearness in time between planning and execution of an action (Chelariu et al., 2002; Moorman & Miner, 1998)

p.2 "Requisite imagination" (Adamski and Westrum, 2003) is a mandatory principle for resilience.

p.2 Though humans might not be well suited or may lack the adequate resources and tools, they will occasionally be required to engage in improvisation. Their ability to improvise successfully should thus be supported by the organization.

p.3 A resilient system must be in a constant preparedness to respond to unforeseen events and surprises.

p.5 improvisation is about interplay of action and interpretation, and about interchangeably looking forward and backward in order to make sense of what is happening.

p.6 Improvisation is needed in situations where unforeseen events occur.

p.6 The ability of a work organization to reconfigure spontaneously in demanding operating situations is a key characteristic of high-reliability organization (e.g., LaPorte & Consolini, 1991). This suggests that "improvising organizations" should allow for reconfiguration of their work organization when this is required.