At the same time as the development of human insulin and insulin pumps, improvements in glucose monitoring were introduced. Although there was initial skepticism if home blood glucose monitoring would be accepted by patients with diabetes, history would confirm that this technology would revolutionize diabetes management and allow patients to titrate blood glucose to normal or near-normal levels. While self monitoring of blood glucose (SMBG) allowed immediate evaluation of diabetes management, the introduction of hemoglobin A1c (A1c, or glycated hemoglobin) around the same time was used as a marker of objective longer-term (about 90 days) glucose control. When hemoglobin is exposed to glucose in the bloodstream, the glucose slowly becomes nonenzymatically bound to the hemogobin in a concentration-dependent fashion. The percentage of hemoglobin molecules that are glycated (bound to glucose) indicates what the average blood glucose concentration has been over the life of the cell. Perhaps as importantly, A1c made it possible for researchers to study the effects of long-term glucose control and the development of vascular complications. New students of diabetes may now find it difficult to appreciate that one of the greatest medical controversies between the discovery of insulin and the early 1990s was the relationship between glucose control and diabetes complications. Improved insulins, pumps, SMBG, and A1c finally allowed this question to be properly studied.