Short answer: Aristoteles (Aristotle) was a Greek philosopher (384–322 BCE), one of the two towering figures of ancient Greek philosophy (with Plato). He founded a comprehensive system spanning logic, metaphysics, natural science, biology, psychology, ethics, political theory, rhetoric, and literary theory, and his writings dominated Western and Islamic thought for many centuries. Below is a structured, reasonably comprehensive overview. If you want more detail on any part, tell me which.

1) Life and context
- Born about 384 BCE in Stagira (Chalcidice), in northern Greece. His father, Nicomachus, was the court physician to the Macedonian king (this gave Aristotle early contact with Macedonian court).
- At about age 17 (c. 367 BCE) he went to Athens and joined Plato’s Academy, remaining for roughly 20 years until Plato’s death (c. 347 BCE).
- After leaving Athens he spent time in Asia Minor and on the island of Lesbos doing biological research, and in 343/342 BCE he was invited to tutor the young Alexander (the Great) at Mieza.
- In 335 BCE he returned to Athens and founded his own school, the Lyceum. The Peripatetic school (from peripatein “to walk”) was associated with him and his school.
- After Alexander’s death and a rise in anti-Macedonian feeling in Athens, Aristotle left the city (c. 323 BCE) and died in 322 BCE at Chalcis (Euboea), reportedly saying he wanted to avoid the appearance of impiety that had condemned Socrates.

2) Works and the textual tradition
- Many of Aristotle’s works survived, often in forms that are lecture notes, draft treatises, or collections from his school rather than polished popular books. The extant corpus was compiled and ordered (in large part) by Andronicus of Rhodes in the 1st century BCE.
- Major groups:
  - Organon (logical works): Categories, On Interpretation, Prior Analytics, Posterior Analytics, Topics, On Sophistical Refutations.
  - Natural philosophy/natural history: Physics, On the Heavens, On Generation and Corruption, Meteorology, History of Animals, Parts of Animals, Motion of Animals, On the Soul (De Anima), On Sense and the Sensible, On Memory and Recollection.
  - Metaphysics: Metaphysics (ta meta ta physika).
  - Practical philosophy: Nicomachean Ethics, Eudemian Ethics, Magna Moralia (attributed), Politics.
  - Rhetoric and Poetics: Rhetoric, Poetics.
  - Minor works: Problems (later), Constitution of the Athenians (rediscovered 1890s; likely from the school), several biological treatises.
- Many works were lost in antiquity; what remains is only part of what he likely wrote. The surviving corpus has been central to Western and Islamic philosophical education.

3) Methodology and approach
- Aristotle combined careful empirical observation (especially in biology) with logical analysis and systematic conceptual classification.
- He emphasized causality and explanation: asking “why” in terms of causes. He is known for articulating four kinds of causes (see below).
- He rejected Plato’s theory of separate, transcendent Forms. Instead he held that form is immanent — formal structure exists in things themselves (hylomorphism: matter + form).
- He is the founder of formal logic in the Western tradition (syllogistic), and introduced systematic categories for analyzing kinds of being and predication.

4) Key doctrines and concepts
- Hylomorphism: Substances are composites of matter (hyle) and form (morphe); form gives actuality and definition to matter.
- Substance (ousia): primary being; individual concrete things are primary substances.
- Potentiality and actuality (dunamis/energeia or entelecheia): change is explained as the actualization of a potential.
- Four causes:
  - Material cause (what something is made of).
  - Formal cause (the form or pattern).
  - Efficient cause (that which produces it).
  - Final cause (the purpose or end — telos).
- Unmoved mover (Prime Mover): In Metaphysics he argues for a highest cause — a necessary actual being that moves others as final cause (object of desire/thought), often interpreted as a kind of divine thought thinking itself.
- Teleology: natural processes are explained in terms of ends or purposes (this was central to his biology and physics).
- Categories: Aristotle’s early logical work lists ten categories (substance, quantity, quality, relation, place, time, position, state, action, affection) as fundamental ways things can be said to be.
- Logic: syllogism (deductive reasoning from premises to conclusion), distinctions between demonstrative knowledge (episteme), dialectical reasoning, and rhetorical persuasion.
- Theory of knowledge: starts from sense perception, builds to memory, experience, induction (epagoge), then to universal principles and demonstrative science.

5) Natural philosophy and biology
- Aristotle carried out extensive empirical observations, especially of animals; he wrote detailed zoological works with classifications and descriptions of anatomy, life cycles, and behavior.
- He sought teleological explanations (organs exist “for” certain functions), and used comparative anatomy.
- In physics and cosmology he posited earth-centered cosmos, natural places, elements (earth, water, air, fire, plus aether for heavenly bodies), and natural/sustained motion conceptions — later superseded by modern physics but influential for centuries.

6) Psychology / De Anima
- Soul (psyche) is the form of a living body: different kinds (vegetative, sensitive, rational).
- Perception and cognition originate in sense experience; intellect has two parts often translated as passive (possible) and active (agent) intellect — much debated in interpretation.
- He develops theory of perception, imagination, memory, and thought.

7) Ethics and political thought
- Nicomachean Ethics is his principal ethical work: central aim is eudaimonia (flourishing, “happiness”) as the highest human good, achieved by rational activity in accord with virtue.
- Virtue ethics: moral virtues are excellences of character, acquired by habituation; virtue is a mean relative to us (doctrine of the mean), between excess and deficiency.
- Practical wisdom (phronesis) is the intellectual virtue needed to apply general principles in concrete circumstances.
- Friendship (philia) and contemplative life are important: Aristotle values the life of theoretical contemplation but also sees political/community life as necessary for providing the conditions for virtue.
- Politics: humans are “political animals”; the polis exists by nature for the sake of the good life. He analyzes constitutions, class structure, and argues for the value of a strong middle class. He defends slavery and asserts a natural basis for it — a view that is morally condemned today.

8) Rhetoric, Poetics, and aesthetics
- Rhetoric: art of persuasion; analyses of ethos (character), pathos (emotion), logos (argument), and rhetorical genres.
- Poetics: analysis of tragedy (plot, character, diction), the concept of catharsis (purging of emotions) and mimesis (imitation). His Poetics heavily shaped literary theory, though only fragments survive for some genres like comedy.

9) Influence and reception
- Antiquity: hugely influential in the Hellenistic world; Peripatetic school continued his work.
- Later antiquity and Byzantium preserved and commented on him.
- Islamic philosophers (Al-Farabi, Avicenna, Averroes) engaged deeply with Aristotelian philosophy, translating and developing it.
- Medieval Christian Scholastics (notably Thomas Aquinas) integrated much of Aristotle with Christian theology; Aristotle became “the Philosopher” in medieval universities.
- Renaissance onward: Aristotelianism dominated science and philosophy until the Scientific Revolution; later centuries criticized and revised his natural philosophy, but his logic, ethics, metaphysical concepts, and political ideas remained central to many debates.
- Modern impact: his logic was gradually superseded by modern symbolic predicate logic; however, his virtue ethics has seen a strong revival in contemporary moral philosophy. His metaphysical categories and notions of substance and causation remain topics of debate; his biological observations are still valued historically.

10) Criticisms and limits
- Scientific errors: many of Aristotle’s physics and cosmology are now known to be incorrect (geocentrism, elemental motion, no notion of inertia), and some of his biological claims are mistaken, though many observations were perceptive.
- Teleology: modern science largely rejects teleological explanations in natural science, though teleological language survives in biology in limited form (functions, evolutionary explanations rather than final causes).
- Ethics and politics: some social doctrines (defense of slavery, views about women’s inferiority) are morally unacceptable by modern standards.
- Logic: his syllogistic system is less expressive than modern predicate logic and was replaced for formal deductive work, though historically foundational.

11) Famous quotations (with sources)
- “All men by nature desire to know.” (Metaphysics, Book I)
- “Man is by nature a political animal.” (Politics, Book I)
- “The good for man is an activity of soul in conformity with excellence or virtue.” (Nicomachean Ethics)
- “The whole is greater than the sum of its parts” — an idea echoed in his discussions of form and unity (not a literal quote, but reflective of his views).

12) Further reading (modern introductions and translations)
- Primary texts: Nicomachean Ethics, Metaphysics, Physics, De Anima, Prior Analytics, Politics, Poetics, Rhetoric (look for translations by W. D. Ross, J. Barnes, H. Rackham, or modern Penguin/Clarendon editions).
- Secondary/introduction: Jonathan Barnes, Aristotle (Oxford); Terence Irwin, Aristotle’s Nicomachean Ethics (commentary/translation); Anthony Kenny, A New History of Western Philosophy (introductory); Sarah Broadie, Aristotle: Nicomachean Ethics (commentary); Christopher Shields, Aristotle (Routledge Philosophers).
- Online resources: Stanford Encyclopedia of Philosophy entry on Aristotle; Internet Encyclopedia of Philosophy.

If you want, I can:
- Give a more detailed account of any single work (e.g., Metaphysics, Nicomachean Ethics) with chapter-by-chapter summary.
- Explain his four causes, hylomorphism, or syllogistic logic in detail with examples.
- Summarize the differences between Plato’s Forms and Aristotle’s forms.
- Provide a reading plan (which texts and translations to start with for a beginner). Which would you like?
