In January 2007, a project was launched by EUROCONTROL with the aim of understanding the new area of Resilience Engineering and its relevance to Air Traffic Management (ATM). Resilience Engineering is developing important tools and methods for both system developers and people responsible for the maintenance and management of system safety, in a number of industries. This White Paper provides an overview of the work carried out and seeks to answer the following questions: - What is Resilience Engineering? - Why do we need it in ATM? - What is the usefulness of performance variability? - What does Resilience Engineering look like in practice? - How does Resilience Engineering fit with other safety methods? - How mature is Resilience Engineering and what is the added value for ATM? The added value of an Resilience Engineering approach is that it provides a way to address the issues of emergent accidents and the often disproportionate consequences that are an outcome of ever more complex technologies and ever more integrated organisations. Resilience methods are likely to be important tools in the management and assurance of ATM safety in the future.