Course
A free, structured XPath course in 19 phases and roughly 107 lessons. Each phase opens with a short reading lesson, then hands you exercises evaluated by the same conformant engine that powers the Sandbox — so what you learn is what actually runs.
The path runs from the tree model through navigation, filtering, functions, axes, and on into XPath 3.1 features that XPath 1.0 has no answer for.
You type an expression, it runs against a real document, and the matched nodes light up in the document view. Hints arrive in graduated steps rather than all at once, and a quiz closes each phase.
New to XML itself? The XML Foundations course covers elements, attributes, well-formedness, and namespaces first.