I think you have to define what improvisation does—not what it is. Improvisation to me means that there is a characteristic spontaneity in the work which makes it appear not to have been planned. I write a very tight script, and from there on in I allow the actors to interpret it the way they wish. But once they choose their way, then I’m extremely disciplined—and they must also be extremely disciplined about their own interpretations. There’s a difference between ad-libbing and improvising, and there’s a difference between not knowing what to do and just saying something. I believe in improvising on the basis of the written word, and not on undisciplined creativity.