It is not just authorized, but authoritative. Indeed, I venture to say that Mr. Moore’s 'Margaret Thatcher' is one of the greatest political biographies ever written.
Moore is certainly on Thatcher’s side. Educated at Eton and Cambridge, he had a distinguished career in the Conservative media as the editor of the Spectator and the Sunday Telegraph. But he is both sympathetic and balanced, never a sycophant.
Moore’s writing is mostly restrained and cool, a nice corrective to Thatcher’s overheated personality. But when he allows himself to be more subjective, his language can be a touch Tory-triumphalist.