Operations Research using open-source tools is a book that is affordable to everyone and uses tools that do not cost you anything. For less than $50, you can begin to learn and apply operations research, which includes analytics, predictive modeling, mathematical optimization and simulation. Plus there are ample examples and exercise incorporating the use of SCILAB, LPSolve and R. In fact, all the graphs and plot in the book were generated with SCILAB and R. Code is provided for every example and solutions are available at the authors website. The book covers the typical topics in a one or two semester upper division undergrad program or can be used in a graduate level course.