An expensive package ...
This package combines three titles from the Charles F. Goldfarb series that have been for sale seperately for some time and are now offered in single box. Of the three titles, the main interest of the "Cookbook" is its emphasis on internationalization, especially character sets, extensive listings of which are provided. However, these listings are available for free on the Internet in a much more convenient electronic format.
The "Handbook" provides a basic introduction to XML, and then goes on to offer hundreds of pages of paid advertising space to suppliers of XML tools to essentially describe why their products are great.
These three titles do not seem to have been written to complement each other and in fact demonstrate sufficient overlap in content. This, combined with the questionable quality of the individual titles, makes one wonder whose interests are served by this package.