The Saud family is the monarchy, which is the state, of Saudi Arabia. This book shows how that state of affairs came to be.
I found the material on the 1930s especially illuminating, because it provides us with a picture of the Saud family, and to a degree a picture of Arabia, before the rest of the world came to appreciate the strategic significance of petroleum, and before the Second World War made all national boundaries something up for negotiation and renegotiation.
We're also treated to an illuminating dicussion of when marriages (and by extension polygamy) is, and when it isn't, a valuable tool for the forging of political alliances. This is an analytical take on a subject usually rushed through with cliches.