Suddenly, in 1939, something long expected came as something most unexpected, as Hitler invaded Poland. Ordinary men and women from all walks of life were suddenly thrown into the most challenging situations, either fighting - on land, sea and in mid-air - or assisting their countries in intelligence duties, code-breaking, sabotage or scientific research. These heroes, many of whom served on the battlefield, were matched by their civilian counterparts, who helped to liberate the free world by deciphering enemy codes, designing faster and better aircraft and inventing war-winning machinery and ordnance. From pathfinding pilots to scientists, from the officers and journalists who were confronted with Hitler's grossest atrocity at Belsen to the inventors of radar - all these characters played a part in hastening the end of the most cataclysmic conflict ever recorded by the camera.