Self-consciously staging itself in the psychotherapy sessions of a disturbed young man, Peter Shaffer's Equus is a shocking exploration of the limits of faith, of the intersecting worlds of the sacred and profane, and of the paltry value of a 'mundane' life, published in Penguin Modern Classics.

When a deranged boy, Alan Strang, blinds six horses with a metal spike he is sentenced to psychiatric treatment. Dr Dysart is the man given the task of uncovering what happened the night Strang committed his crime, but in doing so will open up his own wounds. Dysart struggles in secret to define sanity, to justify his marriage, to account for his career, and finds himself questioning the 'normality' of his way of life. Ultimately, he must ask himself: is it patient or psychiatrist whose life is being laid bare? The most shocking play of its day, Equus uses an act of violence to explore faith, insanity and how the materialism of modern life can destroy humanity's capacity for pain and passion.