The abstract is the entire paper reduced to its essence and may be all that many readers will see. It should contain all of the major elements listed in Table 1, especially introduction, hypothesis, methods, results, and conclusion. Obviously each of these has to be brief, and contain only essential, high-level information. To stay within word limits, and also to maintain reader attention, nonessential data should not be included. The introduction should in one to two sentences bring the reader to the point of expecting the next item (the hypothesis), which should fit within a single sentence. Next should be the overview of the experimental methods/strategy. It should include species and number of subjects (or cells or molecules, as appropriate) including control subjects, and give a high-level statement of the study design. Results should follow, limited to those that are key. If space permits, include data values and statistical outcomes. Finally, present the conclusion allowed by the data, referring back to the hypothesis and whether it is supported or not. In practical terms, it is common to write the first draft of the abstract without too much concern for word limits, just to set the major elements in place, and then refine the text to fit the allowed space in a second step.