The study of operations research (OR) is concerned with mathematical methods and tools for solving problems relating to the allocation of scarce resources subject to constraints. Frequently these problems have to do with determining the least cost or greatest profit possible for a cost or profit function subject to constraints such as capacities and required amounts over a very large number of variables. Important problems within this space include minimum cost routing problems, network maximum flow or minimum cost flow problems, and machine scheduling problems. The growing trends in OR increasingly utilize applications of more than one technique and involve individuals from other disciplines. Moreover, they involve a blend of "hard" and "soft" as well as a mixing of different "hard" or "soft" techniques with the increasing use of multiple methods within one piece of analysis. A creative thinking must look in detail at how those from disciplines outside of OR can come to work in the organizations on multi-disciplinary studies. Those who have come from such backgrounds, clearly share their perspectives and experiences. The field of OR is always changing. Its changes are driven by the technology it uses and that it extends, and the applications that it affects.