Arabia Felix

Thomas had some anthropological interests and believed in the pseudoscience of racial types and craniofacial measuring. He documented or described the peoples in the Rubʻ al-Khali, taking note not only of their skull sizes but also local distinctions between social classes, exorcisms, hunting practices, Islamic and non-Islamic spiritual beliefs, a wife's role and duties, female circumcision, tribal dances, mourning ceremonies, food customs, some local cures for the ailments of people and animals, "the psychology and ethics of the blood-feud," and war, among many other topics. His photographs of the people are scattered throughout the text.