Blind White Fish in Persia by Anthony Smith
This book gives an account of a small Oxford University expedition to Persia in 1950 to bring back specimens of a fish, allegedly white and sightless, which was said to inhabit the underground water-courses of Iran. Though the four young men that made up the expedition failed in their quest, they discovered rural Persia where villagers still led medieval lives. The story includes an account of the qanats - the underground irrigation and tunnels employing ancient technology which still criss-cross the country making life in the desert possible.