JOHN GREHAN has written or edited more than 300 books and magazine articles covering a wide span of military history from the Iron Age to the present war in Afghanistan. His previous publications include The Lines of Torres Vedras: The Cornerstone of Wellington's Strategy in the Peninsular War 1809-12, The Battle of Barossa, and Britains German Allies of the Napoleonic Wars. John has also appeared on local and national radio and television to advise on military history topics. He was the Assistant Editor of Britain at War Magazine from its inception until 2014. John now devotes his time to writing and editing books.