The reader must be warned that this is a modest book, aiming at helpfulness more than erudition. We realized that economics has expanded in this sense too: there are hundreds of eponyms, and the average economist will probably be acquainted with, let alone be able to master, just a number of them. This is the void that the Dictionary is expected to fill, and in a manageable volume: delving into the problems of the sociology of science, dispelling all Mertonian multiple discoveries, and tracing the origins, on so many occasions spurious, of each eponym (cf. ‘Stigler’s Law of Eponymy’ infra), would have meant editing another book, or rather books.