Protagoras

Alone among Plato's works it is a courtroom monologue rather than a dialogue, and with the Euthyphro, Crito and Phaedo it forms the quartet dramatising Socrates' trial and death — the events that turned Plato toward philosophy.

Set in the prison between the Apology's verdict and the Phaedo's execution, it is the shortest of the four last-days dialogues and the one that turns from Socrates' own fate to the citizen's duty toward the state.

One of the short definitional dialogues, in which Socrates hunts a single concept — here holiness — and comes away empty-handed; it opens the tetralogy that runs through the trial to the execution.

A brief, aporetic early piece whose deliberately perverse conclusion has kept it a standing puzzle — and whose authenticity a few scholars still question, though Aristotle already treated it as Plato's.

Among the shortest dialogues, and the first place Plato treats poetry as divine possession rather than craft — a theme he takes up again, far more harshly, in the Republic's quarrel with the poets.

Its authenticity is disputed — unquestioned in antiquity, doubted since Schleiermacher — which is now the salient fact about it; the longer of the two Alcibiades dialogues attached to Plato's name.

An early inquiry into a single virtue, pairing naturally with the Charmides on temperance; the question it leaves open — whether courage is really a form of knowledge — points ahead to the Protagoras.

Generally judged spurious — a post-Platonic imitation carried under his name in the corpus — this short exercise on prayer is useful mainly as a specimen of how the school later wrote in Plato's manner.

A pivot in the corpus, standing between the aporetic early dialogues and the middle-period metaphysics: the theory of recollection and the knowledge/true-belief distinction first surface here, on the road to the Phaedo and Republic.

A comic dialogue framed as Socrates' report to Crito, and the corpus's fullest exhibition of sophistical fallacy — much the same material Aristotle would later systematise in the Sophistical Refutations.

The early companion to the Laches: where that dialogue fails to pin down courage, this one fails to pin down temperance — set just after Socrates' return from Potidaea, among relatives of Plato who became tyrants.

Plato's only dialogue given wholly to language and the correctness of names; hard to date and unusual in the corpus, it stands at the head of a debate the philosophy of language has never closed.

The bridge from the early ethical dialogues to the Republic: its confrontation with Callicles over whether injustice pays sets up the question the Republic devotes its whole length to answering.

One of the shortest early dialogues, and Plato's only sustained treatment of friendship as such; the questions it cannot answer are the ones Aristotle later organises in the Nicomachean Ethics.

Almost entirely a set-piece funeral oration rather than a dialogue; its authenticity is backed by Aristotle's references, and it reads as Plato's deliberately ambiguous parody of Athenian patriotic rhetoric.

The longest and most doctrinally ambitious of the last-days group, and the point where Socrates' conversations give way to Plato's own metaphysics: the theory of Forms stated outright, at the deathbed.

The centre of the corpus and the fullest statement of the middle-period philosophy — the Forms, the tripartite soul, the ideal city — gathering into one work the ethical and political threads of the Gorgias, Meno and Phaedo.

A middle-period masterpiece built as a sequence of set speeches rather than a cross-examination; with the Phaedrus it is Plato's great treatment of erôs, and the source, through Ficino, of the phrase 'Platonic love.'

The turning point where Plato subjects the middle-period Forms to their gravest criticism; its baffling second half became, for the Neoplatonists, the supreme metaphysical text in the whole corpus.

Pairs with the Symposium as Plato's second great study of love, but reaches further — into rhetoric, dialectic and a famous closing critique of writing; unusually, it is set in the countryside outside Athens.

Plato's central inquiry into knowledge, and the first of a late trilogy continued in the Sophist and Statesman; famously it reaches no definition at all, ending in deliberate impasse.

An unfinished late dialogue, broken off in mid-sentence and intended as the sequel to the Timaeus; its importance is almost entirely as the ancient origin of the Atlantis story.

The technical heart of the late trilogy, led by the Eleatic Stranger rather than Socrates; its solution to the puzzle of not-being is Plato's most sustained piece of pure logic and ontology.

The direct sequel to the Sophist, and the corpus's bridge from late metaphysics toward the legislation of the Laws; its claim that expert knowledge outranks written law reconsiders the Republic.

Plato's one work of systematic cosmology, and by far his most influential in the Latin Middle Ages — for centuries the only dialogue available in the West, through Calcidius's partial translation.

Classed among the spurious works and doubted since antiquity, this short dialogue on wealth is carried in the corpus under Plato's name but is very unlikely to be his.

Plato's longest and last dialogue, left unfinished at his death and the only one without Socrates; a practical, law-by-law counterpart to the ideal city of the Republic.

A late and technically demanding dialogue on whether pleasure or wisdom makes a life good; its exact place in the late group is unusually uncertain, and it is Plato's fullest ethics of pleasure.