Are you referring to the essay written by critic Martha Stephens regarding Flannery O'Connor? If so, you can read this right here on eNotes.
To summarize, Stephens divides the story into two parts. The first part, up until the family takes the detour to investigate the grandmother's childhood home, Stephens views as comical. She says that O'Connor initially presents a comic side of the family but as the short story progresses, it becomes a tragic comedy. The grandmother's values are both comical and tragic, especially as they foreshadow what is to become of the family at the hands of the Misfit and all because the family followed the wishes of the grandmother.
Stephens discusses the characters and the plot, giving specific attention to the grandmother's character and how it is the focal point of the action. She believes that the main point of the story takes place in the final conversations between the grandmother and the Misfit and that this section deserves the most careful attention if one is to understand this short story. She also discusses the fact that this was one of O'Connor's favorite stories and explains O'Connor's personal view of this particular short story - "in this story you should be on the lookout for such things as the action of grace in the Grandmother's soul, and not for the dead bodies."