This document provides definitions and explanations of key terms related to the concept of war. It begins by defining war as an armed conflict between two or more opposing entities aimed at achieving a geopolitical goal. Various types of war are described, including civil wars and proxy wars. Motivations for war are discussed, including imperialism, misperceptions between sides, and three universal reasons according to the Talmud: economic reasons, power/pride/personal reasons, and ideology/religion. Economic theories for the causes of war are also outlined, suggesting wars can arise from pursuit of markets and resources. The document serves as an introductory chapter establishing definitions and concepts to understand the discussion of war that will follow.