For a dramatic action to take place , two conditions must be fulfilled: the actors' performance and the audience's observance. In a theatre building these two actions take place in two separate areas. The one where the performance takes place is the playing area (stage) and where the audience watches this is the observing area (auditorium). In all theatre buildings, these two areas need to be linked together directly, or in other words, these two spaces in a usual theatre are adjacent to each other. These two spaces are separated, or connected to each other, by a virtual demarcation line. In history, playing areas and observing-areas went through many formal changes. But in all the known theatre buildings, we observe two kinds of relationship between these two areas:
1 . Frame-stage (proscenium arch theatre),
2 . Space stage.
In the frame-stage, the demarcation line separates the playing area from the observing area as a straight line and its length is the length of the stage facing the audience. The dramatic action takes place on one side of this line (on the stage): and the audience sits across this line and watches the play from the auditorium as if they are looking at a framed picture. An invisible and transparent wall across the proscenium arch separates completely the auditorium from the playing area, the audience from the actors, and thus the act of performing from the act of observance. This separation makes it impossible for a bond or communication to develop between the performers and observers.
In the space stage, the line of separation is extended outwards so that the playing area is extended forwards, toward the observing area. The curved demarcation line is longer, the actors on the stage are closer to the audience and the audience seems deeper and more voluminous. Hence the stage is a larger space and the actors can communicate better with the audience. This sense of depth or volume increases on the U-shaped apron stage, but the actors and audience communicate the best in a real theatre in the round where the audience forms a circle or a rectangle around the playing area.
Throughout the history of theatre, we observe that when the theatre people want to create a closer bond with the audience they have built any kind of the space-stage. But when they want the audience to watch the action, without any participation, from a distance, we see the frame stages (proscenium arch theatres). This book studies the continuous change (and the complex evolution) in theatre buildings in history, between the frame and space stages.