 The ancient tradition assigns one book to Alcmaeon, which came to bear the traditional title of Presocratic treatises, On Nature (DK, A2), although this title probably does not go back to Alcmaeon himself. Favorinus’ report that Alcmaeon was the first to write such a treatise (DK, A1) is almost certainly wrong, since Anaximander wrote before Alcmaeon. Theophrastus’ detailed report of Alcmaeon’s account of the senses (DK, A5) and the fact that Aristotle wrote a treatise in response to Alcmaeon (D.L. V. 25) suggest that the book was available in the fourth century BCE. It is unclear whether Alcmaeon wrote in the Doric dialect of Croton or in the Ionic Greek of the first Presocratics (Burkert, 1972, 222, n. 21). The report that an Alcimon of Croton was the first to write animal fables might be a reference to a poet of a similar name. Fragment 5 in DK (“It is easier to be on one’s guard against an enemy than a friend.”) sounds very much like the moral of such a fable (Gomperz 1953, 64–5). Diels and Kranz (=DK) identify five other fragments of Alcmaeon (Frs. 1, 1a, 2, 3, 4) and arrange the testimonia under 18 headings. Fragments 1a, 3 and 4, however, are really testimonia which use language of a later date, although some of Alcmaeon’s terminology is embedded in them. The three lines of Fragment 1, which probably began the book, and the half line in Fragment 2 are the only continuous texts of Alcmaeon. Another brief fragment/testimonium should be added to the material in DK: “the earth is the mother of plants and the sun their father” (Nicolaus Damascenus, De plantis I 2.44; see Kirk 1956 and Lebedev 1993). There is also the possibility that Fr. 125 of the Spartan poet Alcman (“Experience is the beginning of learning.”) should, in fact, be assigned to Alcmaeon (Lanza 1965; Barnes 1982, 610).