Books are often the only way to get a really good big picture overview of a subject, because of their scale and editorial process. * Blog posts tend to be too

Books are often the only way to get a really good big picture overview of a subject, because of their scale and editorial process. * Blog posts tend to be too short, so you only get some details or a really vague outline. A book can do both big picture and relevant details. * Documentation is usually written by someone who knows the system too well, so too often it leaves out a lot of things that the author thinks are obvious but aren't obvious to readers.