In [1] Islam Unveiled I explain the theological and legal reasons why slavery persists in some Islamic societies — notably Mauritania and Sudan. I had a little bit of information on slavery in Saudi Arabia in there but for reasons I don't recall it didn't make the final draft. Still, slavery was only abolished in Saudi Arabia in 1962, and there are numerous indications that [2] it continues today — including this [3] ad in Saudi paper (which I saw thanks to [4] LGF) offering a 1991 Dodge for a "female servant" from Sri Lanka or India.

And why not? It's taken for granted in the Qur'an (see Suras 2:178, 2:221, 4:92, 5:89, and many more), and that is the foundation of Saudi society. It is also a cornerstone of the oppression of non-Muslims dhimmis, who throughout history have often been enslaved or treated as slaves by their Muslim overlords. The fact that such laws are still on the books ought to be the first concern of human rights organizations worldwide.