This kind of well produced, very well written, very thorough software manual, one that doesn't make assumptions about what knowledge you're bringing to the table, is sorely missing from modern software.
I'd pay $20-30 to have manuals like this for many pieces of modern software.
(OTOH, those pieces of software would need to be more well designed, and more consistent in their design language, in order for a manual like this to be at all useful.)