Over the past 30 years, a considerable body of evidence has revealed that a prior bout of exercise can increase the ability of insulin to stimulate glucose transport and glycogen synthesis in skeletal muscle. Apart from its clinical implications, this work has led to a considerable effort to determine at a molecular level how exercise causes this effect and, in particular, whether it does so by enhancing specific events in the insulin-signaling cascade. The objective of this review is to discuss from a historical perspective how our current thinking in this area has evolved and the people responsible for it. Areas to be discussed include the effect or lack of effect of prior exercise on the insulin-signaling pathway, effects of exercise on the regulation by insulin of the GLUT-4 glucose transporter in muscle, and the emerging role of AMP-activated protein kinase as a mediator of exercise-induced signaling events. In addition, we will discuss briefly some of the avenues that research in this area is likely to follow.