Prof, Irving Fisher (1867-1947) was an American economist, health campaigner, and eugenicist, and one of the earliest American neoclassical economists and, although he was perhaps the first celebrity economist, his reputation today is probably higher than it was in his lifetime. Several terms are named after him, including the Fisher equation, Fisher hypothesis and Fisher separation theorem. The young Irving had mathematical ability and a flair for inventing things. Fisher's best subject was mathematics, but economics better matched his social concerns. He went on to write a doctoral thesis combining both subjects, on mathematical economics. Irving was granted the first Yale Ph. D. in economics, in 1891. He did not realise at the outset that there was already a substantial European literature on mathematical economics. Nevertheless, his thesis made a contribution to European masters such as Francis Edgeworth who recognised it as first rate. Harry Gunnison Brown (1880-1975) was was an...