Former White House Press Secretary Scott McClellan writes in a surprisingly scathing memoir to be published next week that President Bush “veered terribly off course,” was not “open and forthright on Iraq,” and took a “permanent campaign approach” to governing at the expense of candor and competence.

Among the most explosive revelations in the 341-page book, titled “What Happened: Inside the Bush White House and Washington’s Culture of Deception” (Public Affairs, $27.95):

• McClellan charges that Bush relied on “propaganda” to sell the war.

• He says the White House press corps was too easy on the administration during the run-up to the war.

• He admits that some of his own assertions from the briefing room podium turned out to be “badly misguided.”