A startling new book charges that John Kerry accidentally "wounded himself in the buttocks" in Vietnam with a grenade he exploded, then lied to get a medal by saying he had received the injury rescuing one of his crewmen. The book, "Unfit for Command," was released yesterday by Regnery publishers and presents the biggest challenge yet to Kerry's decorated war-record. Based on the accounts of numerous vets, the explosive book claims Kerry's rescue under fire of Jim Rassman — an action that earned Kerry his third Purple Heart and a Bronze Star — didn't happen the way the Democratic nominee...