In the introduction you should clearly identify the key topic-a problem about which you actually going to argue further. That is, to begin with, you must inform the subject of the essay,
to paraphrase it using synonyms of keywords. You have to show that he understood and comprehended the topic. It is also necessary to specify that there are opposing views about this issue, and indicate which position you take. While it is best to use impersonal constructions to emphasize objectivity. The introduction may include a review to the topic. This may be the definition of a key concept or your explanation of how you understand the topic. You can list which aspects of the topic are to discuss and why.