Here is a first attempt to start a wikibook about Mathematica, which is also a sort of meta book. This introductory page of the wikibook is devoted to a general presentation of the project and an abridged table of contents. The details should progressively emigrate to new pages. Please, let's use the discussion page (link in the left pane) to discuss the project and its organization, so this page will progressively evolve to its final destination.
Wikibooks are often considered only as subsets of wikis, which commonly leads to information duplication instead of cross-reference editing. In order to avoid redundancy, we assume here the wiki and the wikibook should more or less be one and the same thing. More precisely, the wikibook is an attempt to give a structured presentation of the wiki content, plus possibly external content, in the more classical form of a book with chapters and sections, or possibly a collection of books. Nevertheless, a wikibook may be richer than an ordinary book thanks to its active cross-references.
So the wikibook basically consists of a collection of pages with pointers to the wiki content and also to external content. Then writing a wikibook more or less amounts to seeking and collecting information, then presenting and evolving a structure for the huge amount of information available on the web. Evolving a wikibook amounts to restructuring it. As a consequence, the wikibook is a sort of meta-book with cross references, that gathers both general and specialized information, basic, intermediate and advanced presentations, theory and practice? Some parts of the wikibook could possibly be printed as classical books or as lecture notes.
Here is a provisional abridged table of contents:
Ingolf Dahl | 
Advanced Directx examples | 
discussion
