Just as all eyes focus on Trafalgar for its bicentenary next year, Andrew Roberts leaps ten years ahead and gives us Waterloo, with the claim that it was the most significant of battles – indeed, that it too changed the world. Roberts always has something original to say, and here he presents a concise account, including most of what we need to know, which is not to say that it is all we want to know.

The decisive factor at Waterloo seems to have been timing. Wellington might have done better if he had cut the Duchess of Richmond's ball in Brussels. Napoleon thought he had time to defeat the British before the Prussians arrived. Throughout the day, attack and counter-attack were launched too early, or