While many students are well aware of the heroism and intrigue of World War II, it is clear that few know what happened in the previous World War. This war became a clear break in terms of history towards the modern world, and the tactics and strategies developed during this war would set the stage for all of the wars since then. This chapter takes great pains discussing the new technological developments that led to this amazingly bloody war and the ways that were developed to try to bypass this technology. We also cover some of the heroes of the war as well as the causes and effects of the war. The problems with the later Treaty of Versailles would create problems that would lead directly to WWII and beyond. Many of the decisions that were made during the peace negotiations can be easily tied to problems in wars much later in history also. The last section covers the rise of Communist Russia, which will obviously cause problems in the west and around the world for decades later.