The biographer of Elizabeth II (Majesty) has now had privileged access to the House of Saud and thus unprecedented entree, for a Western reporter, to Saudi Arabia: the kingdom they created and named after themselves and, with its unexpected, overwhelming wealth, totally control--as a militantly Muslim state. At 656 pages, Lacey's book is scaled to the occasion; and it is neither evasive nor sensational. (Consequently or nonetheless, it has been banned--""on the basis of eighty-two objections""--in Saudi Arabia.) You will understand, by the close, why the Al Saud are not apt to go the way of the Pahlavis; why they are unperturbed by the ""hypocrisy"" of official prohibition and private imbibing; and other curious matters. In some respects, however, there is less here than meets the eye. The first half of the actual text (the last hundred-plus pages contain bibliography, notes, etc.), which has to do with the unification of Arabia by Abdul Aziz (King Ibn Saud), could be condensed into a few explanatory paragraphs: the historical alliance between the Al Saud and fundamentalist, puritanical Wahlabism; the defeat of the rival North Arabian Rasheeds and the pacification of the bedouin tribes; the wresting of the Red Sea coast (including Mecca and Medina) from the hated Hashemites; the role of the fanatical Ikhwan movement and its eventual suppression; the equivocal British presence--now giving, now taking. Instead, these matters are scattered through short chapters constructed around one or another often-minute point--an artificial, halting, circuitous structure (without compensating color or depth of detail) likely to disappoint readers looking for a rousing narrative and frustrate anyone chiefly interested in learning Saudi history. And the pity is that Lacey has been able to pin down some of the elusive facts--to the extent that Abdul Aziz's various myth-making versions of events allow. In the second half, with the search for oil and where it led, the book firms up and acquires some momentum. The Great Divide, then, is the 1973 Yom Kippur War and the Saudi-led OPEC revolt. Before, Lacey is acid on US courtship of Saudi Arabia as a source of abundant cheap off, acute on the consequences for the Saudis--dependence on oil revenues, disillusion (and impotence) in the face of American support for Israel. His privileged sources begin to pay off too--in closely-etched portrayals of Abdul Aziz's decline; of the near-disastrous reign of his sybaritic (yet well-meaning) successor King Saud; of the delicate ouster of Saud by his brothers; of the restorative rule of ascetic, industrious King Faisal (killed by a resentful nephew in 1975). He also fills out the Saudi role in world affairs--notably, Faisal's encouragement of Sadat's 1972 break with the Soviets (and the embittering American non-response). But his grasp of Saudi thinking and purposes is most intensely felt in the final, 1973-and-after, section--where he is able to make sympathetically intelligible, even inescapable, everything from the oil boycott to the Saudis' non-conservation of their one valuable resource, from their tolerance of internal dissidence to their outrage at the TV-film Death of a Princess. Saudis ""do not see why they should not have the best of both worlds""--Western ""evils"" (in measure) and Muslim virtue. Not a great book by any means--but it does give substance to shadows, and seriousness to the long-comical.