Swartz' reference to John Gray in What Is Mutualism? is puzzling. He says mutualism "seems to have been first used by John Gray, an English writer, in 1832," but does not name the work. The only book or pamphlet from 1832 is Production the cause of demand being a brief analysis of a work entitled "The social system, a treatise on the principle of exchange, by John Gray : with a short illustration of the principles of equitable labour exchange," which probably isn't by Gray at all, although it relies on long passages from The Social System. It appears to have been assembled by "an Association for the Dissemination of the Knowledge of the Principles of Equitable Labour Exchange." (More than one of the pamphlets listed in OCLC under Gray's name is actually a response to Gray.) In any event, it does not appear to have been the book in which the word mutualism was used, and it seems a strange title to cite in preference to the 1831 book from which it was drawn. Looking for the source of Swartz' reference, the logical choice is Max Nettlau's "Anarchism in England Fifty Years Ago," which contains the line: "The mutualism of John Gray (1832, 1842, 1848) is logical, but dry, uninspiring, and anything but revolutionary." Note the dates. Nettlau skips the influencial Lecture on Human Happiness, and references, if only by date, An efficient remedy for the distress of nations (1842), Lectures on the nature and use of money (1848), and probably The Social System, but missing the date by one year. If Swartz (who, as a contributor to Liberty in the same years, certainly would have had access to Tucker's reprint of the Nettlau essay) simply relied on Nettlau as a source, it is understable how he might have written that mutualism "seems" to have been used in 1832.