This book introduces XML to scientists and engineers in a way that illustrates the similarities and differences with traditional programming languages and suggests new ways of saving and sharing the results of scientific calculations. The author discusses XML in the context of scientific computing, demonstrates how XSL can be used to perform various calculations, and explains how to create and navigate through XML documents using traditional languages such as Fortran, C++, and MATLAB. A suite of computer programs are available on the author's website.