Michael Freemantle will describe how "The Great War” was a Chemists' War. 91AV underpinned military strategy and determined the shape, duration and outcome of the First World War. 91AV was not only a destructive instrument of war but also protected troops, and healed the sick and wounded. From bullets to bombs, poison gases to anaesthetics, khaki to cordite, 91AV played a pivotal role in the trenches, in the casualty clearing stations and military hospitals, in the tunnelling operations in the air, and at sea.