Bibliotheca historica (Ancient Greek: Βιβλιοθήκη Ἱστορική, "Historical Library") is a work of universal history by Diodorus Siculus. It consisted of forty books, which were divided into three sections. The first six books are geographical in theme, and describe the history and culture of Egypt (book I), of Mesopotamia, India, Scythia, and Arabia (II), of North Africa (III), and of Greece and Europe (IV–VI). In the next section (books VII–XVII), he recounts the history of the world starting with the Trojan War, down to the death of Alexander the Great. The last section (books XVII to the end) concern the historical events from the successors of Alexander down to either 60 BC or the beginning of Caesar's Gallic War in 59 BC. (The end has been lost, so it is unclear whether Diodorus reached the beginning of the Gallic War, as he promised at the beginning of his work, or, as evidence suggests, old and tired from his labors he stopped short at 60 BC.) He selected the name "Bibliotheca" in acknowledgement that he was assembling a composite work from many sources. Of the authors he drew from, some who have been identified include: Hecataeus of Abdera, Ctesias of Cnidus, Ephorus, Theopompus, Hieronymus of Cardia, Duris of Samos, Diyllus, Philistus, Timaeus, Polybius and Posidonius.
Diodorus' immense work has not survived intact; only the first five books and books 11 through 20 remain. The rest exists only in fragments preserved in Photius and the Excerpta of Constantine Porphyrogenitus.