Introductory and concluding paragraphs function together as the frame around the argument of your essay. Or, using the visual image of book-ends holding the books – the body of your essay – together. It is important to write the introduction and the conclusion in one sitting, so that they match in mirror image to create a complete framework.
An introduction should seek to engage readers so that they will become invested in your writing. In some contexts this means finding a way to persuade a reader who is reading 60 papers on the same topic that yours is worth paying special attention to. In other contexts this means helping a reader already committed to your work to recognize what unusual or exciting question your paper will address.
Writing introductions to discussion essays - DC IELTS
Just as the introductory paragraph is written after the argument or case of the middle paragraphs has been written, so the title is written after the essay is completed. In this way, it can signpost what the reader can expect from the essay as a whole.