Robert Green & Elizabeth Morgan 
World War I and the Rise of Global Conflict [PDF ebook] 

World War I forever changed how nations engage in warfare. Airplanes, tanks, and submarines were used on a larger scale than ever before. This volume examines the root causes of World War I, which escalated from a small political incident into a massive global crisis. It also details the impact of this war in its immediate aftermath and in the decades that followed. Readers will be engaged by the accessible text, which is enhanced with historical photographs, primary sources, and in-depth sidebars.