The prompt book, also called transcript, the bible or sometimes simply "the book," is the copy of a production script that contains the information necessary to create a theatrical production from the ground up. It is a compilation of all blocking, business, light, speech and sound cues, lists of properties, drawings of the set, contact information for the cast and crew, and any other relevant information that might be necessary to help the production run smoothly and nicely.
In modern theatrical productions, the prompt book is generally maintained and kept by the stage manager, with differences in the specific construction and organization to suit the style of the stage manager keeping the book, and the type of production (legitimate theatre, musical theatre, dance, opera, etc.).
Modern prompt books will tend to be constructed using binders with multiple tab dividers, with the page of the production attached to a larger sheet of paper to provide more margin space for taking notes. Markings to the script (for cues, notes, etc.) are typically done in pencil, and either in the margins or on the blank side of the back of the opposing page.
In situations where there are multiple stage managers or assistants, it is not uncommon for many copies of the prompt book to exist. Generally a lead stage manager will keep the master book, which is then copied by assistants on a nightly basis to account for any new information inserted during rehearsals, productions, and meetings. While all prompt books will contain some of the same basic information (script, cast list, contact information, set drawings, etc.), there is no official standard, and individual stage managers will determine the best way of keeping books for themselves and the productions they manage. While Actors' Equity Association, the union governing professional stage managers in the United States, does not publish any official pragma for a prompt book, such practices are often covered as part of college curricula, and many books exist on the subject.
Prompt books were originally used by a prompter to much the same effect that they are today used by deputy stage managers. During the period spanning from the mid 17th through the early 19th centuries, rehearsal periods were generally very short by modern standards: a period of 1–2 weeks for three hours a day was common. Performances were likewise unpolished by modern standards, even when taking into account the theatrical conventions of the time, and so it was necessary to have a prompter standing by to assist actors with lines, blocking, and business—all of which the prompter would need to have recorded in their book.