The contribution made by a joint author must be an “authorial” one. [In a previous case decided by Laddie J] … the person who laboured extensively in setting the specification for computer software, and in fixing errors and bugs in it, was not a joint author with the person who actually wrote the software. What counts as an authorial contribution may vary depending on the type of work, however. A screenplay is concerned with providing a plot and dialogue which enable the reader to visualise what is going to happen on the screen, and get a feeling for what the audience will experience. The author is directly concerned with such matters as the choice of characters and the incidents in the film which will bring out those characters, and display their emotions. The storyline and plot are also of direct concern to the author and are a part of what he or she creates. These aspects of a screenplay can, in principle, amount to a contribution of an authorial kind.