{MathBook \XML} {Robert Beezer} {There is a need for a source format that explicitly captures the structure of a scholarly document (such as a research article or a textbook) and subsequently allows for automated conversion to the wide variety of output formats that are currently popular. MathBook \XML\ is an \XML\ application designed for this purpose. It is lightweight and practical, with an emphasis on being a tool that is simple for authors to use, especially those creating science and mathematics texts. \XSL\ transformations to \LaTeX\ and \HTML\ are under heavy development now. The \HTML\ output employs MathJax to render \LaTeX\ syntax for mathematics and \code{knowls} for fine subdivisions of the content and cross-referenced material. It is easy for an author to specify the content of embedded Sage cells, Geogebra demonstrations, or video. Conversions to other formats, such as Sage and SageMathCloud worksheets, iPython notebooks, and \acro{EPUB} will be made as the project matures. I will present an overview of the \XML\ elements being built, the design decisions behind their creation, the output of several of the current conversions, and plans for continued development.}