Mark Ravenhill quotes:

Even within single sentences, there are sudden changes of register. And when the travellers go to Venice, they see a play by Voltaire! This is a novel [Candid] which has narratives within narratives, such as when Cunégonde recounts her story.

Optimism and happiness are not the same thing, but they are becoming interchangeable, and it seemed to me that Voltaire's Candide gave me a way into something important happening in modern-day culture.

Translating Candide into tweets has really deepened my appreciation of his writing - it wouldn't work so well with nineteenth-century authors. Every single sentence in Voltaire seems to advance the story, and yet stand alone as a sound-bite.

Voltaire's novel [Candid] offers us parallel universes, the possibility of entering into alternative worlds existing side by side, and this is something quite modern. Nested narratives and parallel universes are popular at the moment in many different art forms.

It's a book that makes me laugh and think - it would be very hard to like someone who didn't enjoy Candide!

Rereading Candide, I was struck by the link between optimism and the optimal, the idea that we have been placed in this optimal world rather than some other.

There is the question of language. Although the play [Candid] is not written in strict verse form, there is an underlying beat of rhyming couplets, with echoes of Pope and the tradition of eighteenth-century philosophical verse.

I have adapted the whole book [Candid] into tweets of 140 characters, and these are being sent out daily, at the rate of eight tweets per day .

Also, everyone thinks they know Candide - you hear people described as 'Panglossian'. So if Candide appears on a poster, it feels familiar.

Candide is one of those books I read when I was young and that I come back to regularly.

Theatre within theatre, when characters sees themselves on stage, always raises philosophical questions of choice and free will.

The American journalist Barbara Ehrenreich has written about this in her book Smile or Die: How Positive Thinking Fooled America and the World (2009) . She talks about the happiness industry, the rise of medication to make us happy and of self-help books, and the influence of all this on religion. In many ways religion has become another form of self-help. We all suffer from over-exposure to positive thinking.

The title's so upfront. It gives fair warning about the play's content. I'm writing about a kind of disenchantment, an anger, but quite a cool 90's anger, at a time when we're not very good at openly being angry. . . . I don't think I ever thought the title was titillating. I thought it was incredibly catchy. If the play is about the reduction in human relations down to a consumerist rationale, then thematically, the title is entirely linked into the thesis of the play.

I have not chosen to create a linear story, but a series of different narratives: in the end there are five plays that almost, but don't quite, add up to one play... I start with the story of Candide, being performed as a play within a play, to bring the audience up to speed with the story.

In the business world, the idea of positive thinking is absolutely entrenched.

The financial crisis happened because no-one could actually say out loud how bad things were...

There is a remarkable nimbleness of style, a balancing act of tone, in Voltaire, which is hard to bring off on stage. When you speak the words out loud, the effect is very different from when you read them. So one needs to do something new with a stage performance, not simply 'tell the story'.

Twenty years ago, when you bumped into someone and asked how they were, they would say, 'Mustn't grumble' or 'Getting by': now they feel obliged to say 'Just great!'. In both cases, the reply is just a social nicety, but the framework has changed, it's as if it's become a social duty to express happiness.

We are now so far advanced in our denial of evil that we want to rationalise it away.