Oh, the grand old Duke of York, He had ten thousand men;He marched them up to the top of the hill,And he marched them down again.And when they were up, they were up,And when they were down, they were down,And when they were only half-way up,They were neither up nor down.Prince Frederick, Duke of York and Albany is famous because of the nursery rhyme which ridicules him for poor leadership but, as Derek Winterbottom’s biography shows, he was far from incompetent as a commander. What is more, the famous rhyme does not even hint at his achievements as commander-in-chief of the British army during the Napoleonic Wars. His career as a commander and administrator and his scandalous private life are long overdue for reassessment, and that is what this perceptive and absorbing study provides. He transformed the British military machine, and the Duke of Wellington admitted that without York’s reforms he would not have had the army that fought so well in the Peninsular War and at Waterloo. York also led a turbulent personal life which was engulfed by scandal when his mistress was accused of using her influence over him to obtain promotion for ambitious officers. Today the Duke of York is a neglected, often derided figure. This biography should go some way towards restoring his reputation as a commander and military reformer.