  Albert’s masterwork in logic is a summa entitled the Perutilis logica (Very Useful Logic). He also composed a voluminous collection of Sophismata, which examines numerous sentences that raise difficulties of interpretation due to the presence of syncategorematic words — i.e., terms such as quantifiers and certain prepositions, which, according to medieval logicians, do not have a proper and determinate signification but rather modify the signification of the other terms in the propositions in which they occur. He also wrote several question commentaries: Quaestiones on the Ars Vetus or Old Logic (i.e., the Isagoge of Porphyry and Aristotle’s Categories and De Interpretatione), Quaestiones on the Posterior Analytics, and a series of 25 Quaestiones logicales (Logical Questions), addressed to semantic problems and the status of logic. Of dubious authenticity are the treatises De consequentiis (On Consequences) and De locis dialecticis (On Dialectical Topics), which have been attributed to him in a Parisian manuscript.