I would think that one of the strongest ways to introduce an essay like this is to simply open with the idea that the drama is about Proctor. I think that Miller makes it clear that the development of the play is about Proctor's tragic condition. Miller uses Proctor's tragic condition as the way in which he can develop both a sense of empathy for Proctor but also compel the audience to see why Proctor did what he did. Introducing an essay on Proctor can include the idea that Miller wants the audience to approach and absorb how Proctor's actions taken were the only possible actions taken given the sense of character and dignity that he emerges with by the end of the drama. Miller is deliberate in making the entire drama about Proctor and how he must come to this decision, a tough one and one that is not easily embraced. His tragic condition is one that makes him approachable to modern readers, who, too, must face the inevitable challenge of how individual subjectivity meshes in the face of overwhelming objective elements. I think that a good introduction would bring out how Proctor's predicament is the central issue of the play. His tragic state is what enables the drama to emerge as a grand morality play where the reader/ audience has little choice but to ask if they would possess the level of moral courage that Proctor shows at its conclusion.