The governance and evaluation of 'megaprojects' - that is, large-scale, complex, high-stakes infrastructure projects usually commissioned by governments and delivered through partnerships between public and private organisations - is receiving increased attention. However, megaproject evaluation has hitherto largely adopted a linear-rationalist perspective to explain the frequent failure of such projects to meet the 'iron triangle' of performance criteria: delivering on time, within budget, and according to specifications. This approach recommends greater control and accountability to remedy megaproject 'pathologies'.Drawing on empirical examples mainly from the transport sector and radioactive waste disposal, this book offers new perspectives to megaproject evaluation. Comprising contributions from leading experts in project evaluation and appraisal, this collection opens up new avenues by suggesting two ways of improving megaproject evaluation: 1) approaches that go beyond the dominant linearrationalist notion of policy processes, and emphasise instead the objective of opening up appraisal processes in order to enhance learning and reflexivity; and 2) approaches that extend evaluative criteria beyond the 'iron triangle', to cover the various socioeconomic impacts and preconditions for project success.This volume will be of great relevance to scholars and practitioners with an interest in megaprojects, energy and climate policy, radioactive waste management, urban design, and project planning and management.