The only rule which Aristotle lays down concerning the dramatic action is that, in common with all other forms of art, a tragedy must have an internal unity, so that every part of it is in an organic relationship to the whole and no part can be changed or left out without detracting from the economy of the play. No dramatic critic has ever dissented from this unity of action; but the unities of time and place were in fact read into the Poetics by theoreticians of the New Learning (Jean de La Taille) and other writers (Jean Vauquelin de la Fresnaye and Jean Mairet). The support which the unities received from Cardinal Richelieu eventually secured their complete triumph and Pierre Corneille, who had not conformed to them in his earlier plays, did so from the time of Le Cid (1636) onwards. But even he found them a tiresome imposition. Only by a very ready suspension of disbelief can we accept that in the space of twenty-four hours El Cid kills Chimène's father in a duel, overwhelms the Moorish invaders during the night and fights a second duel only a few hours after the enemy has fled. These discrepancies – and others besides, which Corneille admits to in his Examen of the play – are obvious even to the most inattentive spectator.

Unlike his rival, who crams into his plays “quantité d'incidents qui ne se pourraient passer qu'en un mois”, Racine describes fluctuating states of mind which, in the rapidly mounting tension, are brought abruptly to a crisis from which there is no retreat. The so-called Aristotelian rules happen to suit this type of drama perfectly since they lead the playwright to concentrate the tragic action on those few hours when, after months or years of emotional tension, a new event supervenes and precipitates the catastrophe.

The most striking evidence of Racine's success in fitting his tragedies into this very stringent framework is that, when watching them, we cease to be aware that the unities exist. Not long before he wrote Phèdre, the same subject had been dealt with by Gabriel Gilbert and Mathieu Bidar, both of whom had kept Hippolyte off stage after Act IV. Racine, on the other hand, brings him into Act V scene 1, the last line of which is only seventy or eighty lines earlier than Théramène's récit in V 6. In the four minutes which these lines take to recite the young prince has gone out with Théramène, has met, fought and been killed by the monster, and Théramène has come back to announce his master's death. Furthermore, Aricie only leaves the stage at the end of V 3, and therefore in the space of two short scenes has met her dying lover on the seashore and has taken her leave of him! These chronological inconsistencies pass unnoticed in the theatre.

Racine invariably observes the unity of place. A room in Pyrrhus's palace at Buthrotum; an antechamber separating the apartments of Titus and Bérénice in Rome; Agamemnon's camp at Aulis; an antechamber in the temple at Jerusalem: by choosing such vague and remote settings Racine gives his plays a universal character, and the presentation of conflicting and hesitating states of mind is not hampered by an undue insistence on material surroundings. At times, of course, the unity of place leads to slightly far-fetched meetings: why, for instance, does Pyrrhus come to see Oreste (Act I Sc. 2), rather than the other way around, except to conform to this rule? Lastly, the unity of place necessitates the récit and this again is in complete harmony with Racine's fundamental aims: how would Andromaque gain by our being able to see Pyrrhus and his bride approach and enter the temple? The important fact is the effect of Cléone's words upon Hermione. Oreste's relating to Hermione the murder of Pyrrhus is the supreme irony of the play. Théramène's récit describes, in the most memorable and poetic language, an event which would be infinitely less moving if we were to see it imperfectly represented upon the stage.

As regards the unity of action, Racine differs sharply from William Shakespeare in excluding minor plots (compare the parallel themes of blind and unnatural fatherhood and the retribution it invokes, in King Lear) and in ruling out the comic element. The fact that, let us say, Act II scene 5 of Andromaque or many of the scenes of Alexandre le Grand and Mithridate have comic undertones is beside the point. Will Andromaque agree to marry Pyrrhus? Will Agamemnon sacrifice Iphigénie? Can Esther persuade her husband to spare the Jews? The plots of Bajazet, Phèdre and Athalie are scarcely more complex than the rest.

Racine restricts his vocabulary to a mere 800 words. He rules out all workaday expressions since, although the Greeks could call a spade a spade, he does not believe that this is possible in Latin or French. The unities are strictly observed, for only the final stage of a prolonged crisis is described. The number of characters, all of them royal, is kept down to the barest minimum. Action on stage is all but eliminated. The mangled Hippolyte is not brought back, as is the Hippolytus of Euripides. The one exception to this is that Atalide stabs herself before the audience; but this is acceptable in a play conspicuous for its savagery and Oriental colour.

The quality of Racine's poetry is perhaps his greatest contribution to French literature. His use of the alexandrine poetic line is considered exceptional in its harmony, simplicity and elegance.

Racine's work faced many criticisms from his contemporaries. One was the lack of historic veracity in plays such as Britannicus (1668) and Mithridate (1673). Racine was quick to point out that his greatest critics- his rival dramatists- were among the biggest offenders in this respect. Another major criticism levelled at him was the lack of incident in his tragedy, Bérénice (1670). Racine's response was that the greatest tragedy does not necessarily consist in bloodshed and death.

As with any contributor to the Western Canon, Racine has been subjected to many generations of literary criticism. His works have evoked in audiences and critics a wide range of responses, ranging from reverence to revulsion. In his book Racine: A Study, Philip Butler of the University of Wisconsin broke the main criticisms of Racine down by century to best portray the almost constantly shifting perception of the playwright and his works.