Infrastructure projects represent one of the largest asset classes globally with the estimated cost of potential new projects planned to 2030 totalling US$70 trn. The sector splits into social infrastructure which is the group of projects that support urban living and economic infrastructure that, following the recession that began 2007/8, has become the global economic methodology du jour to stimulate economic growth. However, unless the host state has surplus financial resources, as has China and the Gulf states, large scale investment may be not be affordable given the capacity constraints and fragility of the international capital markets. Moreover the majority of large complex infrastructure projects are delivered late and over budget. Whatever the initial estimates and plans, sponsors face project distress usually in the last quarter of the development with budget increases ranging from 40% to over 100%. Many major projects are socially necessary but sponsors will fail if they persist in trying to attract investment by pretending that projects are financially viable using the criteria employed by commercial concerns. A new methodology is required. This book explores the reasons these large projects rarely conform to their original plan and what can be done about it. It also examines how the trend to greater complexity will exacerbate this problem unless a new methodology is adopted. The book concludes that unless more realism is introduced developed nations will be unable to renew their infrastructure and developing nations will not be able to establish the foundation of a modern economy. The author is a director of the Institute for Infrastructure Studies and consults globally.