XQuery, The XML Query Language is intended to be both an introduction to XQuery for beginners as well as a reference for more advanced users. It is assumed that the reader is familiar with XML 1.0, but previous knowledge of XML Schema, XPath, or XSLT is not necessary, though certainly helps to have things in context.

The book covers XQuery from the beginning to the end. It discusses important aspects such as the data model, type system, path navigation, iteration, construction, text processing, functions, type operators as well as information beyond the standard, and it provides a look at the future of XQuery. It gives exact details as to how to apply XQuery in practice and how it can be useful. 

The book's format is practical, and it provides hundreds of examples the reader can try out. However, note that the book is implementation independant, which means it doesn't provide any information about specific XQuery implementations. At the book's web site there are references to XQuery implementations and a couple of words about their current status.

Organization

The book is separated into four parts.  It has 505 pages in 14 chapters and 5 appendices including the index and bibliography.

Part I: Foundations

1. A Tour of XQuery
2. Data Model and Type System
3. Navigation
4. Functions and Modules

Part II: Core Language Features

5. Basic Expressions
6. Iteration
7. Constructing XML
8. Text Processing
9. Type Operators

Part III: Application

10. Practical Examples
11. Surprises
12. XQuery Serialization
13. Query Optimization
14. Beyond the Standard

Part IV: Reference

A. Data Model and Type System Reference
B. Expression Reference
C. Function Reference
D. Regular Expressions
E. Grammar

Bibliography
Index

Resources

Book's website maintained by the author:
http://www.qbrundage.com/xquery

Addison-Wesley's web page:
http://www.awprofessional.com/isapi/product_id~{32F4CE04-2E8E-46AB-9F08-4C592AEA9640}/catalog/product.asp