Book excerpt: Delay and disruption often impacts entire projects and is prevalent throughout the entire construction and engineering industries - no project or construction professional is immune to the effects. This book is aimed at any construction professional anywhere in the world who is involved in preparing, assessing, managing and/or deciding issues concerning the assessment of additional time to complete the work, and also additional payment for delay and/or disruption to the progress of a construction or engineering project. Delay and disruption is endemic in the construction industry and leads to time and cost overruns. It is therefore essential that delays and/or disruptions are identified early so that corrective action can be taken. However, when delay and/or disruption actually occurs, the issue of quantifying the period of any delay, the effects of disruption, and the quantification of the resulting loss during, and especially at the end, of a project is complicated.