The book describes the British Army of 1940 and outlines the early stages of the campaign before explaining the context of Gort's decision and why it was made. Then, using British and German sources, it shows how the British doggedly defended their line against heavy German attacks, and demonstrates that the Expeditionary Force was far more than the badly equipped and under trained army which many historians have represented it as. This fresh look at the campaign also casts new light on other aspects such as the impact of the Luftwaffe and the Dunkirk evacuation itself.