The Defense Department is most unhappy, saying the book reveals classified information — though it hasn’t said what that information is. (Publisher Dutton Books has said there’s nothing classified in it.)

The Pentagon hasn’t taken any formal action against the author save to notify him on Aug. 30 that he was “in material breach and violation of the non-disclosure agreements he’d signed,” and that he never submitted the manuscript for a security review. It warned him the government was considering “all [legal] remedies” against him.

But the book has been a runaway best-seller and folks at the Defense Department want to read it if it’s okay to do so.

Well, we’re happy to say that you can buy it and read it, though you must be careful.

According to a Sept. 20 memo we got from DOD security director Timothy Davis, Pentagon spokesman George Little said recently that “No Easy Day,” which goes by the acronym NED, “contains classified and sensitive unclassified information.”

So “in response to requests for guidance” Davis wrote in his memo “For DOD Security Directors,” here’s some official “guidance concerning NED.”

According to the memo, DoD personnel:

       * “are free to purchase NED;

        * “are not required to store NED in [secure] containers . . . unless classified statements in the book have been identified;

        * “shall not discuss potentially classified and sensitive unclassified information with persons who do not have an official need to know and an appropriate security clearance;

        * “who possess either firsthand knowledge of, or suspect information within NED to be classified or sensitive, shall not publically speculate or discuss potentially classified or sensitive unclassified information outside official . . .channels. . .;

        * “are prohibited from using unclassified government computer systems to discuss potentially classified or sensitive contents of NED, and [no] online discussions via social networking or media sites” about classified stuff “that may be contained in NED.”

        Hard to say what the “potentially” classified stuff is. So, until they tell you what the bad stuff is, it’s safe to buy NED and even to read it but don’t underline it and don’t talk about it — except to say “cool book, great cover,” stuff like that.