This open access book addresses theoretical objectives and operational issues for the conceptualisation and development of a resilience monitoring tool for energy systems. Based on the results of the project "ReMoDigital - Resilience Monitoring for the Digitalisation of the energy transition" supported by the German Federal Ministry for Economic Affairs and Climate Action, it offers a multidisciplinary perspective on the process of building resilient digital energy system. The book is structured in three main parts. In the first part, a theoretical basis is provided regarding resilience in relation to complex systems. In the second part, a predominant focus is placed upon governance issues associated to resilience. In the third part, the emphasis lies on how resilience has been - or can be - operationalised within various contexts of energy systems, including electricity grids, energy supply, transport systems, and digitalisation technologies. The book concludes with a synthesis on the main lessons-learned and with key recommendations distilled from all individual contributions. Overall, the book offers a comprehensive guide on the stepwise development of future resilient low-carbon energy systems, and addresses researchers, professionals and policy makers involved in the digitalised energy system transition.