The purpose of having an introductory paragraph when writing a thesis paper (for ‣) is to immediately and concisely provide a rationale for conducting a research study. An introductory paragraph states in no uncertain terms the significance of the researchable topic by providing context: background information that relates to a problem relevant to a target audience.
A hook typically includes a famous quote, essential (deep-thinking, profound, etc.) question, or an impactful, relevant, surprising, etc. fact or statistic. When using a famous quote, include the famous person who mentioned it or "anonymous". Using an essential question will be the only time that a question is to be used throughout the rest of your literature review (except for the research questions). Avoid rhetorical questions and questions as headings. Finally, using a fact or statistic as a hook is the only one of the three that requires a citation and reference (according to APA, 7th edition). Generally, a one-sentence hook is your best bet (less is more).
After hooking the audience, describe the context of the problem in about three-to-five sentences. Include at least one citation that supports the problem based on the literature (primary research articles). Consider the questions words when deciding on what to say about the problem: what, how, why, etc., thinking about any related background information necessary to provide context. Focus only on the problem that supports your research in your introductory paragraph.
The thesis statement should begin with a (contrasting) transition (i.e., introductory phrase, subordinating clause, or sentence connector) from the context of the problem to a clearly stated "answer"; that is, your thesis statement is a potential solution to the problem stated earlier. Also, think of the thesis statement as the one-sentence "answer" to your primary research question. The thesis statement should be one sentence that occurs at the end of the introductory paragraph, and should include the main two-to-four points to be discussed throughout the body of the literature review. See Thesis statement and skeleton outline.