It should make the "story" of your work clear and interesting to the reader. An introduction contains a section on the significance of the subject matter, reviewing the most pertinent literature as background information and introducing the methodologicial approach. It provides the reader with the information necessary to comprehend the topic

and to understand how and why you formulated the problem the way you did. It briefly states subject, goals, purposes, importance, methods, audience and anticipated form of the results. The last paragraph should be a definition of the question addressed and a description of how your study attempts to answer that question.