When it comes to “written by” credits, writing a script involves two main processes. Coming up with the story, plot characters etc and the actual act of sitting down and typing out the script. Often times, especially in television, two writers will work on an episode but only one of the writers will write the actual episode while the other writer helped with the outline, plotting etc. In this case, the writer who actually wrote the script would get a “teleplay by” credit and the other writer would get a “story by” credit. In other words, a “story by” credit is usually accompanied by a “teleplay by” credit if the script is not written by both writers.