The story I heard is that senior CIA staffers gave him permission to publish anonymously thinking that the book was potentially damaging to Bush's re-election campaign (which may be one reason the knives are out as we speak). It is, evidently, equally critical of senior CIA staffers, or at least that was the author's intention. That agency is currently in the process of a major flushing.
That's what I understood the story to be as well, but someone had to sign off on this deal and whoever that was needs to go down the toilet as well. Not only is the CIA going to be purged, so is the State Department