"Castes and Tribes of Southern India. Vol. 4 of 7" by Edgar Thurston is a seven-volume encyclopedia published in 1909. Part of the British government's Ethnographic Survey of India, this ambitious work documents over 300 castes and tribes across southern India, covering 40 million people. Thurston employed anthropometric measurements to investigate social groups, though his subjects often met him with suspicion and fear. The work represents both a significant ethnographic record and a controversial example of colonial-era racial classification theories applied to Indian society.