Our man in Whitehall . . . former Foreign Secretaries Lords Clarendon and Salisbury look down upon the Hon. David Gore-Booth, British ambassador to Saudi Arabia, as he makes his way up the Grand Staircase of the Foreign Office in London, captured by David Secombe, whose atmospheric photographs adorn True Brits (BBC Books, $288), Ruth Dudley Edwards' study of the Diplomatic Service. Dr Edwards visited 21 posts around the world to provide this snapshot of an institution disparagingly referred to by one British newspaper: 'They seem to think that the Foreign Office's job is to look after foreigners.' She supplies a fair-minded investigation into the rigours of the diplomatist's life although the occasionally uncritical gaze may irritate some.