‘The seventeenth century is a very special period in human history,’ says A C Grayling on the opening page of The Age of Genius. ‘It is in fact the epoch in the history of the human mind.’

This is quite a claim, and Grayling goes about supporting it in rather an unusual way. Instead of the learned disquisition on Hobbes, Locke and Descartes that one might expect from such an eminent philosopher, the first third of the book – a hundred pages in total – offers a blow-by-blow account of the Thirty Years’ War, from the Defenestration of Prague right through to the Peace of Westphalia. We read about Tilly’s victory over Christian of Anhalt at the Battle of the White Mountain, the sack of Magdeburg and the death of Wallenstein, the Diet of Regensburg and the Edict of Restitution.

Now, God knows, anyone who can steer this particular reader through the labyrinth of diets and edicts and treaties that populate the Thirty Years’ War deserves the highest praise. And Grayling is a model of clarity. Even when Emperor Ferdinand gives command of the imperial armies to Archduke Ferdinand, who