The first covers mythic history up to the destruction of Troy, arranged geographically, describing regions around the world from Egypt, India and Arabia to Europe.

Only Jerome, in his Chronicon under the "year of Abraham 1968" (49 BC), writes, "Diodorus of Sicily, a writer of Greek history, became illustrious".

However, his English translator, Charles Henry Oldfather, remarks on the "striking coincidence"[3] that one of only two known Greek inscriptions from Agyrium (Inscriptiones Graecae XIV, 588) is the tombstone of one "Diodorus, the son of Apollonius" (“Διόδωρος ∙ Ἀπολλωνίου”) .

The last section (books XVII to the end) concerns the historical events from the successors of Alexander down to either 60 BC or the beginning of Julius Caesar's Gallic Wars.

Identified authors on whose works he drew include Hecataeus of Abdera, Ctesias of Cnidus, Ephorus, Theopompus, Hieronymus of Cardia, Duris of Samos, Diyllus, Philistus, Timaeus, Polybius, and Posidonius.