1. Prior Analytics
It is quite simple to the student of math and logic today, but it was a leap forward in the formalization of logic unseen yet in humanity. If one reads the dialogues of Plato, you can see the similarities in reasoning and logic, but Aristotle first tried defining and formalizing logic that applies to all things.
The language is not very different from what was see in logic in style even.
For let A belong to every B and B to some C. Then, if to be predicated of every is what was said in the beginning, it is necessary for A to belong to some C.
Logic and set theory go hand in hand.
Similarly, if A is predicated of no B and B of every C, it is necessary that A will belong to no C.
Computer science, math, and logic all deal with abstractions. But even more so, it is an abstraction of abstractions. Plato's dialogues contained abstractions already on things such as justice and love. Aristotle's abstraction goes a step further, and deals with premises as such, not "justice", but the bare Ps and Qs of logic.
Author: Aristotle
Original date: ca. 350 BCE