Michael Billington: The first thing to say is that to choose a hundred plays covering a period from 1945 up to the present is an incredibly difficult thing to do and when I first looked at this selection of plays I thought, absolutely astonishing really, you know, because it seems to me, obviously its divided up into decades and what the list does is find the key plays. You know, I'm looking at the first list and Waiting for Godot has to be in there, Look Back in Anger has to be in the second list, etc. the key plays from each decade. And I thought yes, and also it covers different nationalities, it covers agendas; male and female, and it also it covers racial diversity. But than as with any list, when you look at it more closely, you begin to think 'I wonder what happened to X, Y, Z?' so with each period I could come up with some suggestions for plays that could have been included.