A lot of literature presents XPath as though using it is rather like navigating a filesystem: the tags' identifiers are completely taken for granted, and shorthand like ., .., or // often is introduced early on. This article demonstrates exactly how to use XPath to the exclusion of shorthand: which is to say, solely by means of axis specifiers and node tests, and with the use of identifiers confined to predicates.
The XML we'll work on is simple on its face. As a former bookseller, I've made it personal: