Robert Charles "Bob" Vaughan FRS (born 24 March 1945) is a British mathematician, working in the field of analytic number theory.Since 1999 he has been Professor at Pennsylvania State University, and since 1990 Fellow of the Royal Society. He did his PhD at the University of London under supervision of Theodor Estermann. He supervised Trevor Wooley's PhD.His main research interest is number theory. His Erd?s number is 1.In 2012 he became a fellow of the American Mathematical Society.