In 1996 prof Hox wrote a short book to introduce (graduate) students to multilevel analysis. This book, Applied Multilevel Analysis, is available on the publications section of his homepage as a downloadable pdf-file. However, it was slowly becoming outdated, and at some point prof Hox decided to write a new and much expanded version. That book has become Multilevel Analysis, Techniques and Applications, published by Lawrence Erlbaum Associates.

For the moment, you can view the contents of the book. There is a copy of the first two chapters if you are interested in a preview. An errata file is also available. Finally, datasets that are mentioned for the examples in the first version of the book are available for SPSS/Windows, SPSS/Portable, EXCEL and in RAW DATA format.

Hox,  J. (2002). Multilevel analysis: Techniques and applications. Mahwah, N.J: Lawrence Erlbaum Associates.