 His book, "The Demand for Money", was published in four editions from 1969 through 1993 (with slightly altered subtitles), initially setting forth the stability of the relationship between income and the demand for money and later taking into consideration the effects of legal, technological, and institutional changes on the demand for money.The book has been translated into French, Spanish, Italian, Japanese, and Chinese.His continued work on the demand for money through the 1990s and into the 21st century (with William B.P.