The State Department is ""the nation's first line of defense""; yet its head remains ""neither more nor less than the President allows him to be."" Such are the conclusions of this fat, vivaciously detailed, self-consciously literary guide by a veteran foreign correspondent, now chief of the Cleveland Plain Dealer's Washington bureau. Leacacos reviews the traditional suspicion of the American public and its grass-roots representatives toward foreign-policy machinations. Then he outlines the internal organization at Foggy Bottom, the ""inter-agency imbroglio,"" and the contributions of intelligence services to puissant diplomacy, as well as State's relations with Congress and the President. The discussion of Secretaries of State is particularly interesting (why did Rusk say he'd never write his memoirs?). It will appeal to general readers who want to transcend gossip or civics-class platitudes, although serious analysts will find it shallow and overwritten.