Authors should provide a cover letter that explains 'in their words' why the new work should be published in a top-tier journal.
Often we receive manuscripts submitted with a brief cover letter that states simply “Dear editor, please consider our manuscript. Sincerely,” and then is signed by the corresponding author(s) without further description or comment on the new work. Such cover letters offer no guidance for the editors as to why the topic or experimental question addressed in the new work might be of broad interest to the immunology community. Likewise, no clue is provided about how big an advance the new findings are over previously published work. Such authors miss an opportunity to be their own 'best advocate' in communicating the merits of their paper.
Nature Immunology, like other Nature-branded journals, expects authors to submit their 'best' work for consideration for future publication in the journal. Not every manuscript fits that description, although saying this is not the same as stating that the work is not publishable elsewhere. We receive many good manuscripts that present solid experimental findings but that might be considered as 'too specialized' or 'incremental' or that might serve as a 'resource finding' or 'tool'. These manuscripts certainly should be published, as they will no doubt be of benefit to the community. However, such work tends not to fit the category of papers that can profoundly influence the future direction of a research area. Readers and referees, in their comments to the editors, continually reinforce the notion of 'sufficient new insight' that is expected for papers published in top-tier journals.
The cover letter initiates a dialog between the authors and the editors. Authors can present their cases in a one- to two-page cover letter that highlights the context of their experimental question and its relevance to the broader research community, the novelty of the new work, and the way that it advances our understanding beyond previous publications. In other words, “Why do you think your current work belongs in a top-tier journal?” In cases where previous work has addressed a similar problem but conflicting or competing hypotheses might exist to explain diverse results, the authors might frame their manuscript in light of how it provides definitive experimental evidence in support of a certain hypothesis. Alternatively, the authors might argue why existing hypotheses fail to fully recapitulate more physiological scenarios or that certain 'contextual' considerations (for example, tissue-specific or pathogen-specific immune responses) might underlie apparent discrepancies in the literature. Thus, the cover letter should state how the new work serves to resolve the current confusing swirl of conflicting data and thereby may clarify the situation to allow the field to move forward on a more solid footing.
This brief description provided in the cover letter is treated as confidential and is accessible only to the editorial staff. Should a manuscript be sent out for external review, the cover letter is not shown to the referees. This editorial policy serves to allay any fears that the cover letter might be considered as boasting by the authors or as an opportunity to 'hype' the new findings. Similarly, the authors can convey to the editors in the cover letter whether they are aware of competing work and whether they seek an expedited review process. The authors might wish to exclude certain individuals as referees, and they can explain in their cover letter why such individuals might have a potential conflict of interest. Authors can likewise alert the editors if they are in communication with another group that is preparing a complementary manuscript and if they wish to 'co-submit' their manuscripts. This information assists the editors in determining how quickly we need to act on a manuscript and in adjusting our workloads appropriately.
The cover letter also serves to whet the appetite of the editors for the manuscript. That said, each new manuscript submitted to the journal is read and discussed by the editorial staff. Thus, we consider every manuscript submitted to the journal—there is no need to make a special request for us to do so. When an editor reads a cover letter, a number of questions might arise. We anticipate that these points will be addressed in the full manuscript, and so reading the letter serves to generate a list of points to look for in the text and figures. A good cover letter that faithfully represents the content of the manuscript can also reduce the likelihood that the manuscript will be misinterpreted. It is disappointing (and time-consuming) for the editors if authors overstate the results contained in their manuscript, so that on reading we fail to find the promised “exciting results.” A fear that we might have missed something prompts us to spend extra time searching for the “definitive evidence” heralded by the authors. For those manuscripts that might be considered somewhat borderline in warranting external review, we often go back to the cover letter to see what the authors themselves describe as the manuscript's major strengths and the new insights that it provides. Many times, such information can be sufficient to tip the balance toward sending the manuscript out to the experts for their evaluation of its technical merits and novelty.
As authors, you know the work described in your manuscripts better than anyone. Why not use a cover letter to express why others should be as excited by the new work as you are? Be your own best advocate.