Fender introduced the Jazz Bass in 1960 as a "deluxe" model to augment the Precision Bass. Since it's debut the Jazz has stayed remarkably similar to it's original design.
There have however been many smaller changes over the years that are important not only to it's history but also has great year indicator for vintage bass buffs.
The 1960 Fender Jazz Bass had two single coil pickups with stacked knob concentric controls. The top knob would adjust the pickup volume and the bottom knob would adjust the tone of that pickup.