Everything is documented

In addition to the open source code, there are active efforts to provide documentation suitable for novices and advanced users. One of the best examples are the dozens of HOWTOs, which contain detailed information on common and uncommon tasks, such as getting Linux and Windows to dual-boot, or setting up a home Ethernet, or setting up a software RAID system.

The Linux Documentation Project develops documentation for all aspects of Linux, from installation to administration to development, and also contains links to other documentation such as references books, development guides, and more.

There is no need in the Linux community for a book like "Undocumented Windows", because the documentation is open, the developers are open, and the source is open.