What the Butler Saw is definitely the pinnacle of Joe Orton's humour; it was the last play before he was brutally murdered one year later.
The storyline is far too difficult to explain, but in very vague summary, it concerns a series of mistaken identities and one-liners that happen in a psychiatrist's office when an adulterous seedy affair with his potential secretary goes horribly wrong.
The play begins in a traditional note with a basic set up of mistaken identity beginning the comedy, however the introduction of more characters and complications means the plot gets thicker and more humorous by the minute. The farce becomes more and more riotously funny, and twist follows twist until the climactic end that makes a mockery of the obligatory resolution that occurs at the end of normal farces.
Throughout the play, the comedy becomes darker and more sinister, encompassing the themes of rape, incest, adultery and the mal treatment of the mentally ill.
This is one of few play scripts that made me laugh out loud when reading it, and when I saw it performed the whole audience laughed themselves hoarse and snorted like demented whales the whole way through. This is possibly best comic play this century and should easily measure up to Coward and Wilde in the greatest humour of all time.