Theorizing about the relationship between geography and security is one of the oldest and most central themes of Western political science. Modern geopolitical thinking appeared in the late nineteenth and early twentieth centuries, differing from its predecessors in its emphasis on technological change and global systems of power. In vogue before and through the world wars, geopolitics fell out of favor by the second half of the century, accused of everything from environmental determinism to simplistic binary categorization. Today, however, the subject is undergoing a revival -- perhaps based on the recognition that global political changes in the twenty-first century may stem not simply from human culture and institutions but also the geographical environment.

The Influence of Sea Power Upon History, 1660-1783. By A. T. Mahan. Little, Brown, 1890.
Purchase at B& | Purchase at

Admiral Alfred Thayer Mahan was a U.S. naval officer who became world famous for his geopolitical theorizing. The core of Mahan's thesis rested on the relationship between the political control of the sea and the impact of a powerful navy on a state's foreign policy. From these two factors, Mahan attempted to predict the role that naval power would play in U.S. foreign policy. In its heyday, the book was lauded in the United Kingdom and elsewhere; Kaiser Wilhelm II ordered a copy placed in the wardroom of every ship in the Imperial German navy. Although much criticized today, Mahan's work can be credited with uncovering the essential elements of sea power and demonstrating that there are important economic prerequisites for possessing a navy. He provided a rationale for the turn-of-the-century transition of the U.S. Navy from a brown-water force to one that could project and sustain power globally.

Democratic Ideals and Reality: A Study in the Politics of Reconstruction. By Halford J. Mackinder. Henry Holt, 1919.
Mackinder: Geography as an Aid to Statecraft. By W. H. Parker. Oxford University Press, 1982.

Halford Mackinder was the British founding father of modern geopolitics. In 1904, he described an area roughly contiguous with today's Russian Federation as the "eternal geographical pivot of history." In this book, 15 years later, he coined the terms "Heartland" to describe that space and "World Island" to refer to the joint landmass of Europe, Asia, and Africa. Mackinder argued that geography conditions political and strategic outcomes without rigidly determining them, and that geography, demography, and economic success are interrelated. The key to future peace, he claimed, lay in resolving the relationship between the German and Slavic peoples in Eastern Europe. He summed up his theory in an unforgettable catechism: "Who rules East Europe commands the Heartland; who rules the Heartland commands the World Island; who rules the World Island commands the World." W. H. Parker's biography provides insight into the polymath that Mackinder was and an overview of his diverse and accomplished career. More can be found on Mackinder and his legacy at

America's Strategy in World Politics: The United States and the Balance of Power. By Nicholas J. Spykman. Harcourt Brace, 1942.
Purchase at B& | Purchase at

Like Mackinder, Nicholas Spykman was driven by the desire to describe, prescribe, and predict. His 1942 book represented a systematic attempt to apply geopolitics to the American case. He stressed the importance of a global balance-of-power policy, with the United States acting as the balancer -- a role that could be played only if the United States maintained a margin of superiority around the Eurasian littoral, or "rimland," keeping the Soviet Union penned up inside. "Because of the inadequacy of the Arctic Coast as an outlet to the ocean," he wrote, "the great heartland can find access to the sea only by routes that cross the encircling mountain barrier and border zone beyond. The only exit routes are through the Baltic and Black Seas and by the overland routes through the North German plain between the Scandinavian massif and the Carpathians." Spykman's book caught the moment when the geographical scope of U.S. grand strategy was expanding to a global scale. He argued that a postwar return to isolationism was unwise, and his geopolitical perspective provided a rationale for a U.S. commitment to maintaining an equilibrium of power on the Eurasian continent.  

Great Powers and Geopolitical Change. By Jakub J. Grygiel. Johns Hopkins University Press, 2006.
Purchase at B& | Purchase at

Jakub Grygiel's book uses historical case studies to analyze how great powers have responded to such dramatic geopolitical changes as the discovery of new trade routes and continents. He finds that the great powers' success or failure was shaped in part by the location of resources, the layout of trade networks, and the stability of state boundaries. According to Grygiel, a country's strategic response to geography remains one of the most salient factors in establishing and maintaining power in the international arena, as states can increase and maintain their positions of power by pursuing a geostrategy that focuses on controlling resources and lines of communication.

Geopolitics, Geography, and Strategy. Edited by Colin S. Gray and Geoffrey Sloan. Routledge, 1999.
Purchase at B& | Purchase at

The diverse contributions in this collection cover everything from Mahan, Mackinder, and other theorists to subjects such as the influence of weather during the "age of sail," geography in the space age, and the renewed popularity of geopolitics in post-Soviet Russia. Taken together, the chapters underline the point that geography is the mother of strategy, setting the conditions for attack and defense on land, on sea, and even in the air.

  • GEOFFREY SLOAN is Director of the Graduate Institute for Political and International Studies at the University of Reading.
  • More By Geoffrey Sloan