The MathBook standard distribution contains examples of MathBook documents, an explanation on how to extend MathBook and some XSL stylesheets to get you started. The basic structure of a MathBook document is quite similar to a DocBook document. MathBook is DocBook + Mathematics + Interactivity. If you don't use interactivity the MathBook DTD will be able to validate the static document. If you use interactivity you will have to use the code shipped in the demo to validate your interactive MathBook document.
The interactive demo below contains an implementation of all the basic interactivity defined for MathBook. If you want to start authoring in an interactive context using MathBook we recommend you give it a try.