The Servian commentaries on Vergil are doubly distinguished: they are among the very few ancient commentaries on classical Latin texts to survive essentially intact; and they exist in two radically different forms-the original commentary created by the grammarian Servius early in the fifth century, emphasizing grammar and syntax, and an augmented version produced in the seventh century when a reader blended his Servius with much other recherché ancient lore. In the 1920s, the medievalist Edward Kennard Rand undertook to produce a truly modern edition that would fully reveal for the first time the character of the commentaries' two versions. All did not go smoothly, however: a volume devoted to Aeneid 1-2 appeared in 1946, and another, with the commentaries on Aeneid 3-5, in 1965; this edition of the commentaries on Aeneid 9-12 is the first new contribution to the series to appear in more than fifty years. On his death in 2013, Charles E. Murgia left publishable versions of the text, upper and lower critical apparatuses, and large parts of the introduction, and he had gathered most of the data for a testimonial apparatus. Robert A. Kaster completed the work on the testimonia and introduction (using some of Murgia's other writings to supplement the latter), added some subsidiary elements, and prepared the whole for publication. Thanks primarily to Murgia's work, this edition is superior to its predecessors in the series, and to all other editions of Servius, in every respect.