A bassist is a musician who plays the bass guitar or double bass, providing the low-frequency foundation in a musical group. Their role is crucial in various genres, including rock, jazz, and classical, as they create rhythm and harmony that supports other instruments. Bassist techniques can vary, including fingerstyle, slapping, and using a pick. They often work closely with the drummer to establish the groove of a song. Famous bassists, like Paul McCartney and Jaco Pastorius, have significantly influenced music, showcasing the instrument's versatility and importance in a band.