Historians often write long books to prove that history has a recurring pattern. Jan Rüger has written a long book to prove that there is no such pattern. That might sound like a negative, rather depressing exercise. But it isn’t. Great Powers swims along like a river in spate, swirling up alluring backwaters and diving into pools full of surprises.

Rüger’s prime target is Paul Kennedy’s highly influential The Rise and Fall of the Great Powers (1987), which argued that, as a general rule, nations which expand economically are bound to clash with declining nations trying to cling to the status quo. That, Kennedy asserted, is what happened in the case of Britain and Germany: once Germany had overtaken Britain, it was bound to launch a military challenge. Hence the First World War. Rival historians, such as Niall Ferguson, contend that, no, the Great War was a tragic accident which could have been avoided if only Britain had kept out of European quarrels.

This book declares that both models are deeply flawed. According to Rüger, ‘the tragic outcome which saw Britain and Germany take up arms against each other was neither accidental nor inevitable’. The two terrible wars were the result of deliberate decisions taken at the time which could have been taken