This is, in a way, a guided tour through the ages of theatre by way of the different kinds of actor that have lifted the calling from the second oldest profession in the world to a position of world celebrity and lordships. At heart, however, actors are still gypsies, still on the move, still looking out for the chance to sell their lies to an audience as they find them.

Actors have their tricks and their ploys, their habits and superstitions. They never whistle backstage and they try not to quote Macbeth. Theatre abounds in rites and practices and here John Cairney lets you into the secret of some of them. When does the ghost walk for instance? Why 'break a leg'?

Theatre styles are constantly changing, yet an actor remains much the same - a performer trying to make an audience feel what he's thinking. And an audience would be very surprised if they knew what he was thinking.