Taking a mathematician"s perspective, this book concentrates on the quantitative content of modelling in Operational Research, and on the decision element, which is fundamental to the identity of Operational Research throughout. The book looks briefly at a selection of techniques, and some of the quantitative features of the use of such techniques, and gives a general examination of postoptimality and sensitivity analysis using the models developed. Using the same techniques material a framework is developed for problem formulation and for an examination of the role of measurement in Operational Research.