Billy's Bag is an instrumental track by Billy Preston. It appeared on his album The Most Exciting Organ Ever. The fully instrumental album was released in January 1965. Billy's Bag was a favorite among British musicians and club-goers at the time. It helped establish Preston not just as a session musician, but as a solo instrumentalist in his own right.
Billy's Bag bridges the sacred and the profane, fusing the deep, bold sound of the church with the razzle-dazzle of R&B. The song showcases his blend of gospel roots, soulful grooves, and funky rhythm, years before funk fully exploded in popular music. Even today, it’s often cited as a classic example of mid-60s Hammond organ soul.