The vision of nuclear strategy as a means to prevent war remains a powerful but contested idea in international politics. As global rivalries intensify and nuclear arsenals expand, the risk of conflict seems more pronounced than ever. Read by Helen Lloyd. Image: A photograph of nuclear testing at Pacific Island test sites. Credit: EMU history / Alamy Stock Photo

Over the last decade, NATO has embarked on a significant process of military and political adaptation to ensure it can effectively enable the collective defence of allies in a competitive, contested and unpredictable world. Read by Helen Lloyd. Image: NATO flag waving in the wind. Credit: Zoonar GmbH / Alamy Stock Photo 

Through his visionary leadership, inspired rhetoric, and willingness to compromise, John F. Kennedy summoned the narrative of American hope, his most powerful and enduring legacy. Read by Helen Lloyd. Image: Senator John F. Kennedy at Hyannis Port. Credit: Phillip Harrington / Alamy Stock Photo

Like it or not, Japan has become one of the most critical actors in contemporary international politics. Read by Helen Lloyd. Image: A naval exercise conducted by Japan. Credit: World History Archive / Alamy Stock Photo 

Foundation myths based on the lives of heroic figures are often used by leaders to affirm their own authority — but they can also inspire wider society. Read by Helen Lloyd. Image: Statue showing the mythological origins of Roman society. Credit: LatitudeStock / Alamy Stock Photo

The US must adopt a grand strategy of democratic expansion. Only then can global security be established. Read by Helen Lloyd. Image: American Second World War-era poster. Credit: Mouseion Archives / Alamy Stock Photo 

The tumultuous relationship between Red China and the Soviet Union hints at an uncertain future for the Sino-Russian partnership. Read by Helen Lloyd. Image: Sino-Soviet propaganda poster. Credit: Album / Alamy Stock Photo

Stagnation at home and turmoil abroad demand a radical rethink of how – and why – Britain forges its future leaders. Read by Helen Lloyd. Image: The Treasury building in Whitehall, London. Credit: mauritius images GmbH / Alamy Stock Photo 

Few ancient monarchs have enjoyed such a consistent positive reputation as Cyrus the Great. Perhaps it’s time to become reacquainted. Read by Helen Lloyd. Image: The Tomb of Cyrus, Iran. Photograph taken in 1898. Credit: Penta Springs Limited / Alamy Stock Photo 

Catherine II’s inoculation against smallpox was an extraordinary act of political self-creation. Read by Helen Lloyd. Image: A portrait of Catherine the Great (1729-1796) by Alexey Antropov. Credit: Pictorial Press Ltd / Alamy Stock Photo