Bluegrass is a genre of American roots music that originated in the 1940s, primarily influenced by Appalachian folk, jazz, and blues. It typically features acoustic instruments such as the banjo, mandolin, fiddle, guitar, and bass. The music is characterized by its fast tempos, intricate melodies, and tight vocal harmonies. The genre was popularized by musicians like Bill Monroe, who is often referred to as the "Father of Bluegrass." Bluegrass music often includes themes of rural life, love, and hardship, and it is commonly performed in informal settings, such as festivals and jam sessions.