I've heard that things like "ethics" and "politics" are not actual books written by Aristotle, but are instead manuscripts of notes of lectures he gave. Is this true for all, some, or none of his works? Were any destroyed and lost permanently? Do we know he was a real person?
According to Jonathan Barnes, in his book Aristotle, one of Aristotle's ancient biographers remarks that "he wrote a large number of books which I have thought it appropriate to list because of his excellence in every field": there follows a list of 150 books. Curiously, the list does not include all of Aristotle's works. Indeed, it does not include his two most highly regarded works - Metaphysics and Nicomachean Ethics. Of all of the listed works, barely one-fifth (approx. 30) have survived.
Again, according to Barnes, most of the surviving works were peharps not intended to be read; it seems likely that the works that survive are made up of Aristotle's own lecture notes and not intended for public dissemination. The two works cited above, Metaphysics and Nicomachean Ethics, appear to be put together by later editors. According to Barnes, Nicomachean Ethics is evidently not a unitary work, and Metaphysics is "plainly" a set of essays rather than a continuous work.
Barnes supports his claims by noting that Aristotle's works are, for the most part, terse. "His arguments are consise. There are abrupt transitions, inelegant repetitions, and obscure allusions. Paragraphs of continuous exposition are set amongst staccato jottings. The language is spare and sinewy." These features strongly suggest the lecture notes interpretation.
First, Aristotle was a historical person. He lived 384-322 BCE in Greece. He is from Macedonia and went to Athens to start studying with Plato. Aristotle later founded his own school in Athens, the Peripatos. We have enough information about Aristotle to write a biography.
Secondly, Aristotle published two kind of works: Scripts for his students and for his lectures on one hand. On the other hand, dialogues and writings for the public, i.e. for intellectuals who were not formal members of his school. Most part of the former writings are conserved, but nothing of the latter type of his writings.