Prologue.- Part I.- Chapter 1: Reframing energy transitions as resolving accountability crises.- Chapter 2: A typology of practices of legitimation to categorise accountability relations.- Part II.- Chapter 3: Five easy pieces: Legitimation at work in cases related to energy transitions.- Chapter 4: Historicising accountability: Berlin's energy transitions.- Chapter 5: A few reflections on accountability.- Chapter 6: Do climate targets matter? The accountability of target-setting in urban climate and energy policy.- Chapter 7: Governance and legitimation in the transition to Nordic electric mobility.- Chapter 8: Accountability and the regulation of legitimacy: Biodiversity conservation and energy extraction in the American West.- Part III.- Chapter 9: Practices of legitimation and accountability crises in a range of energy transitions.- Chapter 10: Conclusion: Legitimation and accountability in energy transitions research.- Appendix I: A workshop, parallel exhibitions and associated events.- Appendix II: Photos from the events in Bergen, May 2019.