A good many inconveniences attend playgoing in any large city, but the greatest of them is usually the play itself.
Article in the New York Herald Tribune (17 February 1957)
I believe in neither a director’s nor a writer’s theatre, but a theatre of intelligent audiences. I count myself as a member of an intelligent audience, and I wrote to you as such. That you should disagree with me I can understand, but that you should resent my expressing my opinions is something that frankly amazes me. I thought we had outgrown the idea of theatre as a mystic rite born of secret communion between author, director, actors and an empty auditorium.
I doubt if there are very many rational people in this world to whom the word "fuck" is particularly diabolical or revolting or totally forbidden.
Spoken during a discussion on censorship, broadcast live on the BBC program BBC-3, (13 November 1965) Tynan was the first to say this word on British television, leading to an apology from the BBC and several motions in the House of Commons.
A good drama critic is one who perceives what is happening in the theatre of his time. A great drama critic also perceives what is not happening.
Foreword, p. viii
John Osborne spoke out in a vein of ebullient, free-wheeling rancour that betokened the arrival of something new in the theatre — a sophisticated, articulate lower-class. Most of the critics were offended by Jimmy Porter, but not on account of his anger; a working-class hero is expected to be angry. What nettled them was something quite different: his self-confidence. This was no envious inferior whose insecurity they could pity.
"Decade in Retrospect: 1959" (1959), p. 13
When you've seen all of Ionesco's plays, I felt at the end, you've seen one of them.
Review of Victims of Duty by Eugène Ionesco (1960), p. 36
A villain who shares one's guilt is inevitably more attractive than a hero convinced of one's innocence.
The man who reacts to the universe with a cry of impotent anguish is acceptable as an artist only if he can persuade us that he has sanely considered the other possible reactions and found them inadequate.
"Anatomy of the Absurd" (1962), p. 104
How far should one accept the rules of the society in which one lives? To put it another way: at what point does conformity become corruption? Only by answering such questions does the conscience truly define itself.
Review of Le Misanthrope, by Molière, at the Piccadilly (1962), p. 117
When a society has doubts about its future, it tends to produce spokesmen whose main appeal is to the emotions, who argue from intuitions, and whose claim to be truth-bearers rests solely on intense personal feeling.
Review of After the Fall, by Arthur Miller, at the ANTA Washington Square Theatre, New York; Blues for Mister Charlie, by James Baldwin at the ANTA Theatre, New York (1962), p. 143
I attacked those Western playwrights who use their influence and affluence to preach to the world the nihilisticdoctrine that life is pointless and irrationally destructive, and that there is nothing we can do about it. Until everyone is fed, clothed, housed and taught, until human beings have equal leisure to contemplate the overwhelming fact of mortality, we should not (I argued) indulge in the luxury of "privileged despair."
"Conference at Edinburgh" (1963), p. 146
Does the critic wish to influence the kind of film that costs more than £250,000? It is as if he were to send a postcard to General Motors explaining that he would like them to make a raft next year, or a helicopter, instead of a car.
"Footnote on Cinema" (undated), p. 260
Everyone is vulnerable who is at once gifted and gregarious.
Judge and prosecutor had hammered it home that Lady Chatterly was an immoral woman, that she had had sexual relations before marriage, that she had committed adultery under her husband's roof; as if these charges somehow disqualified her from participation in serious literature. Indeed, there were long periods of the trial during which an outsider might well have assumed that a divorce case was being heard.
"Lady Chatterly's Trial (The Old Bailey, 20 October - 2 November 1960)", p. 409
The buttocks are the most aesthetically pleasing part of the body because they are non-functional. Although they conceal an essential orifice, these pointless globes are as near as the human form can ever come to abstract art.
One would have thought that the notion of an impersonal critic was as patently absurd as that of an impersonal person: yet playwrights still cherish it as a sort of holy ideal. Admittedly, we all make mystiques: but this one is particularly wishful. The man who asks for an anonymous, impersonal criticism is trying to elevate criticism to the status of a science; whereas it is, I am afraid, only an art. The critic's business is to write readable English: the playwright's to write speakable English. Beyond that it is every man for himself.
All writing is an antisocial act, since the writer is a man who can speak freely only when alone; to be himself he must lock himself up, to communicate he must cut himself off from all communication; and in this there is something always a little mad.
In most writers, style is a welcome, an invitation, a letting down of the drawbridge between the artist and the world. Shaw had no time for such ruses. Unlike most of his countrymen, he abominated charm, which he regarded as evidence of chronic temperamental weakness.
His puritan, muscular, moor-tramping soul (superbly mirrored in Higgins's hymn to the intellect in Pygmalion) bred in him a loathing of all things, whether poems or gadgets, that were designed to comfort the human condition without actively trying to improve it. (p. 103)
"Bernard Shaw," p. 103
Every speech, for Olivier, is like a mass of marble at which the sculptor chips away until its essential form and meaning are revealed. No matter how ignoble the character he plays, the result is always noble as a work of art.
Her style looks absurdly simple — an effortless act of projection, a serpentine lasso whereby her voice casually winds itself around our most vulnerable fantasies. But it is not easy. It is what remains when ingratiation, sentimentality and the manifold devices of heart-warming crap have been ruthlessly pared away. Steel and silk are left, shining and durable.
I do not see the EEC as a great love affair. It is more like nine middle-aged couples with failing marriages meeting at a Brussels hotel for a group grope.
"This going into Europe will not turn out to be the thrilling mutual exchange supposed. It is more like nine middle aged couples with failing marriages meeting in a darkened bedroom in a Brussels hotel for a group grope." - E.P. Thompson, "On the Europe Debate," The London Times (27 March 1975) 
It is the nature of ambition to make men liars and cheats, to hide the truth in their breasts, and show, like jugglers, another thing in their mouths, to cut all friendships and enmities to the measure of their own interest, and to make a good countenance without the help of good will.
Sallust, Bellum Catilinae, X, 5. This particular translation of the original Latin is from the essay "On Liberty" by Abraham Cowley: "Sallust, therefore, who was well acquainted with them both and with many such-like gentlemen of his time, says, 'That it is the nature of ambition' (Ambitio multos mortales falsos fieri coegit, etc.) 'to make men liars and cheaters; to hide the truth in their breasts, and show, like jugglers, another thing in their mouths; to cut all friendships and enmities to the measure of their own interest, and to make a good countenance without the help of good will.'"  The Wikiquote page for Sallust has the quote and a different translation.