Mithridatic Wars
Only 35 of the 142 books survived. Livy used no titles or period names. He or someone close to him wrote summaries, or "Periochae", of the contents of each book. Books 1 – 140 have them. Their survival, no doubt, can be attributed to their use as a “little Livy,” as the whole work proved to be far too long for any copyist. The events of the Mithridatic Wars survive only in the Periochae.