Abstract
Arrestins have now been implicated in the actions of virtually every G protein-coupled receptor (GPCR) for which they have been examined. Originally discovered for their role in the turnoff of visual perception, their newly discovered pleotropic functions in the cellular and physiological actions of GPCRs not only illuminate new mechanisms of signal transduction but also offer new avenues for therapeutic utility. Below, in this introductory chapter, we provide a short historical description and synopsis of how arrestins conceptually became associated with the function of GPCRs.