Fundamentally, the screenplay is a unique literary form. It is like a musical score, in that it is intended to be interpreted on the basis of other artists’ performance, rather than serving as a finished product for the enjoyment of its audience. For this reason, a screenplay is written using technical jargon and tight, spare prose when describing stage directions. Unlike a novel or short story, a screenplay focuses on describing the literal, visual aspects of the story, rather than on the internal thoughts of its characters. In screenwriting, the aim is to evoke those thoughts and emotions through subtext, action, and symbolism.
Several main screenwriting theories help writers approach the screenplay by systematizing the structure, goals and techniques of writing a script. The most common kinds of theories are structural. Screenwriter William Goldman is widely quoted as saying “Screenplays are structure”.