The Saudis never enjoyed the same kind of intimacy and ease with the Clinton administration as they did with the Bush administrations. The connections, cultivated over a quarter of a century, are complex and multifarious, emanating outwards from Houston, centred on oil, embracing both the public and private sector activities of the House of Bush, lubricated and driven by money and power. Unger estimates that $1.476bn has made its way over time from the Saudis to the House of Bush, and its allied companies and institutions. He writes: "It could safely be said that never before in history had a presidential candidate - much less a presidential candidate and his father, a former president - been so closely tied financially and personally to the ruling family of another foreign power. Never before had a president's fortunes and public policies been so deeply entwined with another nation."

September 11 placed the relationship between Saudi Arabia and the US under extreme pressure. Unger catalogues the tensions in intimate detail. He describes how the Bush administration has sought to soothe and safeguard the intimacy, failing to ask or pursue crucial questions about the involvement of leading Saudi figures in 9/11. But the relationship between the US and Saudi Arabia - one of the cornerstones of American policy since 1973, and earlier - is now closer to breaking point than ever before. Can the Bush administration continue to turn a blind eye? Will the House of Saud survive? What will the Americans do in response to its likely successor, an aggressively anti-American, fundamentalist regime? What price an American occupation of the world's most important oilfields? The future is, indeed, uncertain.