This is an important reassessment of a critical period in the British Expeditionary Force's fight against the German armies invading France in 1940. On 25 May Lord Gort, the British commander, took the decision to move 5th Division north in order to plug a growing gap in his Army's eastern defences. Over the next three days the division fought a little-known engagement, the Battle of the Ypres-Comines Canal, to hold the Germans at bay while the rest of the BEF retreated towards Dunkirk. 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 undertrained 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.