This title gave me something think about for my own writing project. Much more than a particular topic of focus, that project is waiting one me to go forward for several reasons:

• A target medium, something friendly to a static format (paper, PDF) but not limited by it. Your brain has to index the material it can retain? What is that?
• A hypertext with a strong indexing linker. Think Unix Power Tools but without the frantic rustling of onionskin, plus you add cross-references as you see fit.
• Graphics that are lightweight and hyperlinked.
• Hyperlinked individual diagram components
• Dependence on universal references such as Wikipedia for acronyms, domain-specific terminology, utter jargon, even the occasional quip, be it epithet, epigram, or epitaph
• A built-in highlighting and marginalia scheme, similar to EverNote. Note-taking mode, point, right-click, type, return. It has to be that simple or simpler, or people won't use it.
• Agile/Extreme writing? It seems silly to me that what ostensibly succeeds for large software projects -- a group of people working alone or in pairs "creating the story" or treating code-as-design, can't produce a high-quality text in a unified style. This is in fact my big kvetch with many Wrox titles: everyone's their own top cook, and it shows.

If you've read such a book, please clue me in. But don't respond with anything Head First. They are not an example en pointe, particularly since O'Reilly has mangled that concept into an upscale equivalent of the For Dummies franchise.