The introductory section of an academic essay is supposed to do three things: First, we use it to introduce the subject of the essay, and more specifically, the issue with respect to the subject. The subject might be, say, the ethics of sport hunting. The issue might be whether hunting with bow and arrow is more or less humane than rifle hunting. If the issue is somewhat complex or unfamiliar you may need to spend a bit of time on this introductory section, providing enough background and context for the reader to understand, in rough outline, what the issue is. Second, we state the thesis of the essay. The thesis is the position or stance that the essay is going to take, on the issue in question.