Once called Eastern Ocean, Hindu Ocean, or Indic Ocean, the Indian Ocean is the third-largest of the world’s oceanic divisions after the Pacific and the Atlantic. It covers 20% of Earth’s surface. One of its main characteristics is that it links Asia to the East, with Europe and Africa to the West. It is also the crossroads of many straits and channels: Malacca, Hormuz, Bab el-Mandeb, the Mozambique Channel, etc. At a time when trade routes transit mainly by sea, the role of the Indian Ocean, and more particularly that of its straits, has thus become a major political and economic issue. This issue of études marines, written by both military and civilian specialists, provides insights on the importance of this region where France has strategic interests, despite being far from the mainland.