Originally published in Encore
This is one of the key roles within a production. This role is pivotal to the smooth running of the show. They like the captain at the helm of a ship guiding the cast and crew through the process on stage making sure that it occurs on every performance at the same time and in the same way.
So how does a SM know how and when? Well they have a book called the prompt book. This is basically a copy of the script that has all of the relevant lighting, audio and other cues in it. It will also contain blocking notes of the performers on stage. Blocking you ask? It is where the moves of the performers on and off and around the stage are recorded. This is where the good and the bad stage managers are sorted out. A good stage manager will make sure that all the blocking and cues are there. The more detail the better. As you can see from the example.
This is not the only role an SM does, they help coordinate rehearsals, make sure the bump in is proceeding smoothly. The will also main an up to date cast and crew contact list. Once the show is up and running the show is theirs. They are the one that has to make sure that it runs the same each night, they night to produce a show report for each performance so the production company can see how it is going. They are then the liaison between the Director and the cast and crew.
This only briefly covers the role of the Stage Manager.