This introduction presents an overview of the key concepts discussed in the subsequent chapters of this book. The book describes the general characteristics of transport systems illustrated by analyzing and modelling of performances of the High Speed Rail system. It presents modelling of the resilience of transport systems illustrated by two cases: a logistics networks operating under regular and irregular conditions and an air transport network affected by a large-scale disruptive event. The book covers diverse transport modes and their systems and therefore appearing rather wide and heterogeneous in terms of context and specific topics dealt with, each is actually very coherent regarding the activity carried out—modelling, planning and/or evaluation. It deals with evaluation of the transport system alternatives by using different Multi-Criteria Decision Making methods. Transport planners are engaged in planning adequate transport capacity in the wider social, economic and environmental context.