The first chapter explores the evolution and function of teeth, establishing a foundation for understanding oral anatomy through an evolutionary lens. It begins with the idea that nothing in biology makes sense except in the light of evolution, highlighting how the form and function of teeth are shaped by selective adaptations. Initially, dental structures served functions other than chewing, such as immobilizing prey. Only with the evolution of mammals did chewing become a central function, accompanied by profound anatomical transformations in the orofacial region. The text delves into the origin of teeth in vertebrates—from jawless fish to the first enamel structures found in conodonts—and traces the emergence of biomechanical innovations like tribosphenic teeth in mammals. Mastication, alongside endothermy, marked a turning point in mammalian evolution, enabling greater metabolic efficiency and access to new ecological niches. The diversification of tooth forms became essential to meet rising energy demands, contributing to the extraordinary adaptability of mammals. The entire masticatory system evolved to enhance energy assimilation, establishing teeth as fundamental tools not only for nutrition but also for survival and evolutionary success.