1) First looks 2) Sneak showings 3) Trailers 1) Teasers 2) Trailers 
Performances before the first night (press night) where there is a paying audience. These are not considered part of the run. These performances are the conclusion of the rehearsal process and provide the actors with the chance to experiment on stage in front of an audience. During the previews, the running time and pace of the performance become a...