On 28 January 1742, a ramshackle vessel of patched-together wood and cloth washed up on the coast of Brazil. Inside were thirty enaciated men, barely alive, and they had an extraordinary tale to tell. They were survivors of His Majesty's Ship the 'Wager', which had left England two years earlier on a secret mission during an imperial war with Spain and had been wrecked on a desolate island off the coast of Patagonia. The men, after being marooned for months, built the flimsy craft and sailed for more than a hundred days, traversing nearly 3,000 miles of storm-wracked seas. They were greeted as heroes. 
 
Six months later, another even more decrepit craft landed on the coast of Chile. This boat contained just three castaways and they told a very different story. The thirty sailors who landed in Brazil were not heroes - they were mutineers. As accusations of treachery and murder flew, the Admiralty convened a court-martial to determine who was telling the truth. The stakes were life and death - for whomever the court found guilty could hang. 
 
THE WAGER is a grand tale of human behaviour at the extremes told by one of our greatest non-fiction writers. As always with Grann's work, the incredible twists of the narrative hold the reader spellbound. Most powerfully, he unearths the deeper meaning of the events, showing it was not only the 'Wager's' captain and crew who were on trial - it was the very idea of empire.