Oil is the source of wealth and economic opportunity. Oil is also the root source of global conflict, toxicity and economic disparity. When did oil become such a powerful commodity—during, and in the immediate aftermath of, the First World War. In his groundbreaking book The First World Oil War, Timothy C. Winegard argues that beginning with the First World War, oil became the preeminent commodity to safeguard national security and promote domestic prosperity. For the first time in history, territory was specifically conquered to possess oil fields and resources; vital cogs in the continuation of the industrialized warfare of the Twentieth Century. This original and pioneering study analyzes the evolution of oil as a catalyst for both war and diplomacy, and connects the events of the First World War to contemporary petroleum geo-politics and international aggression.