The book is in three parts. The first part is about Java, with no XML in sight. It covers the basic plumbing of a distributed Web application written in Java. The second part is about XML and XSLT, with very little Java. Our task here is to summarize both standard XML and XSLT and discover good programming practices for them. The third part brings Java and XML together as two well-matched tools for developing the main theme of the book. The theme of the book is meta-programming, that is, writing programs that customize, guide and modify other programs. Meta-programming is not a very new idea (LISP programmers have been doing it for decades) but XML gives it a profoundly new twist. We believe that XML greatly increases the ability of a Competent User Who is Not a Programmer to exercise control over computer programs by editing human-readable text files. In brief, once .ini files and Notepad are replaced with .xml files and a validating XML editor, the possibilities for controlling programs from text files increase immeasurably, perhaps introducing a new way of programming and a new relationship between the user, the programmer and the program. The theme of the book is this collection of new possibilities; its goal is to help bring about the new relationship.