This book seeks to establish more clearly the generic parameters of a successful mega infrastructure project, on the premise that mega infrastructure projects that are completed on time, within budget and to specification can also be built in the wrong place, at the wrong time, and have impacts that serve special interests at the cost of the wider community. The book more particularly refers to mega transport projects and examines their claimed successes and failures beyond the iron-triangle criteria of project management both in terms of agent of change aspirations they may pursue and in the context of longer term sustainable development challenges they are expected to address. Drawing from a case study pool of 30 mega transport projects in ten countries/territories in the developed world, the book investigates the extent to which such projects meet original and emergent objectives. It looks to offer insights into how and why these projects perform as they do and why their treatment of risk, uncertainty and complexity in decision-making can differ from nation to nation, even region to region, and over different temporal contexts. It assesses the suitability of current traditional planning, appraisal and delivery methods of mega infrastructure projects and concludes with a set of ‘lessons’ for key stakeholders.