Different types of manuscripts require different types of introduction sections. For example, an introduction to a book chapter should be vastly broader than one for a case report. Before starting this section, always check instructions. Is an “Introduction” or “Background” required? Are there instructions about what information should be included?
For abstracts and most manuscripts other than reviews and meta-analyses, don’t include overly broad information that your reading audience likely already knows well. A lengthy introduction to your specific topic isn’t necessary for shorter, more focused pieces, like abstracts or general manuscripts. Abstracts and most manuscripts will be submitted to a journal (or conference) focused on the topic of your work, which means the reading audience is already familiar with most of the basics of that field of study.
Therefore, introduce your work by stating exactly what you studied and why. As an example, you can assume your target audience knows the standard treatments for a given disease, so introduce your piece with something along the lines of “We explored a novel combination therapy that may lead to better outcomes over standard management.”
Short and concise introductions are especially important in abstracts and case reports, where word counts are stricter. Whether an abstract is part of a full manuscript or being submitted for a conference, get right to the point. The same applies to case reports.
Longer introductions should, however, be used in review papers and book chapters, when more of a particular topic is being explored. In these writings, incidence, epidemiology, overviews of treatments, or other general facts to inform an audience that may be less familiar with the topic are appropriate.
Finally, a quick note about references in introduction sections – they should always be the most recent, primary sources you can find. If you finish writing your work more than a couple of months after you started, be sure to check for updated references just before submission.
As always, feel free to contact me with any questions about writing an introduction, or for help with locating appropriate references at firstname.lastname@example.org.