Robert J. Lefkowitz, MD is James B. Duke Professor of Medicine and Professor of Biochemistry at the Duke University Medical Center. He has been an Investigator of the Howard Hughes Medical Institute since 1976. Dr. Lefkowitz began his research career in the late 1960’s and early 1970’s, when there was no clear consensus that receptors as conceived of by pharmacologists even existed. His group spent 15 years developing techniques for radioligand binding, solubilization, purification, and reconstitution of the four adrenergic receptors known at the time. In 1986, Dr. Lefkowitz transformed the understanding of what had become known as G protein coupled receptors (GPCRs), when he and his colleagues cloned the gene and cDNA for the β₂ adrenergic receptor, and recognized its sequence homology with rhodopsin, thus establishing them as the first members of a new family of proteins, the Seven Transmembrane Receptors (7TMRs). This superfamily is now known to be the largest, most diverse, and most therapeutically accessible. Since then, Dr. Lefkowitz has continued to revolutionize the GPCR field through the cloning of eight adrenergic receptor subtypes and the first serotonin (5HT1A) receptor; discovery and cloning of the G protein coupled receptor kinases (GRKs) and β-arrestins; and discovery of “biased” signaling through β-arrestins or G proteins. Most recently, he has been applying the tools of structural biology to understand biased signaling at atomic level resolution. He has received numerous awards and honors, including the National Medal of Science, the Shaw Prize, the Albany Prize, and the 2012 Nobel Prize in Chemistry. He was elected to the USA National Academy of Sciences in 1988, the Institute of Medicine in 1994, and the American Academy of Arts and Sciences in 1988.