Alfred G. Gilman was an American pharmacologist and biochemist, best known for his discovery of G-protein. Born to a well-known pharmacologist, Alfred Zack Gilman, he earned his bachelor’s degree from Yale University and his M.D. and Ph. D. from Case Western Reserve University. Subsequently, he joined the School of Medicine, University of Virginia as the Assistant Professor of Pharmacology. It was here that he set out to find the missing link in Martin Rodbell’s work on cyclic AMP and guanosine triphosphate (ATP). The investigation resulted in the discovery of G-protein, an important intermediary between receptors on the cell membrane and subsequent actions inside the cell; a discovery that earned him the Nobel Prize in Physiology or Medicine almost fourteen years later. Meanwhile he accepted the position of the Chairman of the Department of Pharmacology at the Southwestern Medical Center at University of Texas and remained there till his retirement. Afterwards, he was appointed as Chief Scientific Officer at the Cancer Prevention and Research Institute of Texas; but due to commercial and political interference resigned within three years. He lived for another three years before losing his long battle with pancreatic cancer.