The connoisseur has been an influential, if somewhat mysterious, figure in the history of art, responsible for making or breaking high-profile collections and reputations and influencing taste, the art market and the field of art history with their pronouncements. But what did it take to become a connoisseur, and how reliable were the great connoisseurs of previous centuries? With the advent of scientific techniques and artificial intelligence, what future is there for expertise based on the trained eye? This book offers the first history of the art connoisseur, from the Renaissance to the professionalization of the role in the nineteenth century and on to the present day. Featuring portrayals of some of the leading connoisseurs, such as Bernard Berenson, Roberto Longhi and Giovanni Morelli, this is a highly readable history of the extraordinary characters and intellects that shaped the art world through a mixture of intuition, learning and chutzpah.