Case studies from a wide range of sectors (agriculture, industry, trade, transportation, banking, consultancy, government institutions . . . ) are brought together in Quantitative Methods In Management to explore the usefulness and relevance of the application of operations research and management science. Mathematicians and computer scientists may be able to develop quantitative methods for management, but how do these work in practice? Forty practitioners have described and analysed actual projects, from their own experiences, one of which was a failure, the other a success. Certain questions were asked: What was the real problem? What was the approach? What was the real result? What can we learn from it? Evidently, valuable lessons can be gained from the recognition of why applications failed - one person's failure is another's gain.