Seth Godin writes:

Please don’t include the phrase, "I'll keep this brief," in your remarks.

Please don't quote Robert Browning or Ludwig Mies van der Rohe at us. If less is more, just give us less, not an explanation.

Say what you need to say, then leave. Less is actually more, and the length of your speech or your document has nothing at all to do with your impact or your status.

I'd say the same thing for most books, that the core ideas can be expressed and fully articulated in a few pages. The rest is filler. The future of books is short form.