The Aristotle mss., 1603-1704, consists of commentaries on the works of Aristotle. At least half of the volumes concentrate on logic, but other subjects are covered as well, including physics and general philosophy.

A majority of the manuscripts that have identified authors were written by Jesuits: Maur Altomar, Pierre Baron, Jakob Bidermann, Christoph Brandis, Jean de Horion, Nicolas Mohr, Francois Noghera, Jean-Baptiste Weiss, and Joseph Zwinger. A few were written by Benedictines: Ludwig Babenstuber, Simon Fürbas, and Maurus Oberascher. The other authors are Nicolas Chaumorat, Henrich Drophuysen, Andreas Guetmair, Bernhard Ruedorffer, and Eustach Strenzi. Fourteen of the manuscripts do not have named authors.

The commentaries are in Latin, and on occasion include sketches or diagrams. The Baron volume contains a number of portraits, including St. Augustine and Aristotle himself. Each of the two Oberascher volumes contains a copy of the same printed commentary, although the manuscripts themselves are not identical. The manuscript Logica Actualis... (#165) contains not only sketches, but also a Philosophical Family Tree. Another volume, In Universam Aristotelis Logicam (#96) has two unidentified red seals on the verso of one of its final pages.

Printed commentaries purchased by the library in the same collection are cataloged separately and records for them can be found in the Lilly Library catalog.