The Indian Ocean is the world’s third-largest body of water, containing about a fifth of the water on the planet’s surface. Darshana Baruah’s interesting short book treats it in a holistic fashion rather than as a watery adjunct to the continental hinterlands it abuts. Oceanic islands receive attention as actors in their own right; their shifting relations with the great powers form a major theme in the book.

This vast maritime domain is bounded to the west by East Africa and the Arabian Peninsula. The central area consists of India’s coastal waters and the Andaman and Nicobar Islands. To the east, the Indian Ocean takes in the Bay of Bengal and the waters around Indonesia. To the south, it extends all the way to Australia, which also governs the offshore Cocos Islands and Christmas Island. The book takes us from the plight of various indigenous peoples, like the Shompen on Great Nicobar Island, to the future of underwater fibre-optic cables, submarine data centres and deep-sea mining. 

Traversed by a hundred thousand large vessels a year, the Indian Ocean also includes rich fishing grounds and three of the world’s major maritime chokepoints, which are the real concern of Baruah’s book. These are the Strait of Hormuz and the Bab-el-Mandeb to the west and the Strait of