  He is said to have written a single book (papyrus roll), and deposited it in the great temple of Artemis at Ephesus. The story is plausible enough: temples often served as depositories for money and other valuables, and no libraries are known from the time of Heraclitus. The structure of Heraclitus’ book is controversial. It could have consisted of a relatively coherent and consecutive argument. On the other hand, the numerous fragments (over one hundred) that have come down to us do not easily connect with each other, even though they probably constitute a sizable fraction of the whole. Thus it is possible and even likely that the book was composed more of sayings and epigrams than of continuous exposition. In its form, then, it might have looked more like a collection of proverbs such as were ascribed to the seven sages than like a cosmological treatise of the Milesians. Theophrastus, who knew his book, said that it seemed only half-finished, a kind of hodgepodge he attributed to the author’s melancholy.  Diogenes Laertius reports that the work was divided (he does not say by whom) into three sections, one on cosmology, one on politics (and ethics), and one on theology (9.5–6). All these topics are treated in the extant fragments of Heraclitus, though it is often difficult to see what boundaries the work might have drawn between them, since Heraclitus seems to see deep interconnections between science, human affairs, and theology.