A fire extinguisher is a vital tool for managing small fires, with different classes designed for specific fire types, including solids (Class A), flammable liquids (Class B), electrical equipment (Class C), combustible metals (Class D), and cooking oils (Class K). Proper usage involves alerting others, ensuring personal safety, and recognizing escape routes. Fire extinguisher training is crucial to prevent small fires from escalating and to equip individuals with life-saving skills.