This volume comprehensively addresses the issue of uncertainty in civil engineering, from design to construction. Current engineering practice often leaves uncertainty issues aside, despite the fact that new scientific tools have been developed in the past decades that allow a rational description of uncertainties of all kinds, from model uncertainty to data uncertainty. It is the aim of this volume to take a critical look at current engineering risk concepts in order to raise awareness of uncertainty in numerical computations, shortcomings of a strictly probabilistic safety concept, geotechnical models of failure and their construction implications, actual construction, and legal responsibility. In addition, a number of the new procedures for modelling uncertainty are explained. The book is a result of a collaborate effort of mathematicians, engineers and construction managers who met regularly in a post-graduate seminar at the University of Innsbruck during the past years.