I present a brief history of the science of crop to wild gene flow and a glimpse into its future. Scientists have long recognized that crops can spontaneously mate with their wild relatives. However, for reasons probably associated with the cultures of basic vs. applied science, study of that process was largely neglected. The realization that transgenes could end up unintended in wild plants generated a closer examination of the process of crop-to-wild gene flow and its consequences. I expect that this field will continue to grow, with increased emphasis on using transgenic crops themselves as experimental organisms. However, a sister phenomenon, crop-to-crop transgene flow, and its consequences, may prove to be a more urgent emerging issue to be addressed by specialists in transgene flow.