As the First World War loomed, the transatlantic passenger trade was at its peak and, as the enormity of the conflict grew, many liners were conscripted into military service. In an attempted counter-blockade of the UK, German U-boats began sinking Allied merchant vessels, in some cases sparking international outrage. Eventually it was the declaration of unrestricted submarine warfare in 1917 that drew the previously neutral United States into the conflict. By war's end, the U-boats had managed to sink over 5,000 ships, killing 15,000 people in the process. Into the Danger Zone recounts what it was like for both military personnel and civilians alike to experience a sea voyage at a time of war, when they could encounter any number of dangers, including U-boats, mines and enemy surface vessels. Attacks were frequent and tragedy all too common. Using a wealth of unpublished, rare and fascinating first-hand accounts, illustrations and photographs, Fitch and Poirier present an engaging history of this often-neglected chapter of the twentieth century.