This chapter establishes the foundational relevance of mechanisms and machines through a historical and societal lens. It emphasizes how ancient civilizations utilized mechanical innovations to build infrastructure, wage war, and expand territories. Examples include the Egyptian shadoof for irrigation, Chinese south-pointing chariots for navigation, and Archimedean devices in Greece for engineering and warfare. The chapter invites the reader to appreciate the cultural, functional, and technological contexts in which mechanisms evolved, setting the tone for deeper technical exploration. The chapter also presents basic concepts on Mechanism Science, establishing definitions which are necessrary for the development of further topics on mechanism synthesis and analysis. It serves as a conceptual entry point into the discipline.