Research papers like articles, theses, and lab reports almost always require an Abstract, which can be thought of as a special type of summary. The Abstract is the first section of such texts (usually no more than 1–2 paragraphs and/or 150–300 words long), and it should summarize the purpose of the study, its method and/or theoretical approach, and its main findings. The Abstract is an independent text that a reader should be able to understand without reading the longer text that it summarizes.
When writing an Abstract, make sure to provide a clear and accurate picture of your study so that the reader can decide whether or not the paper is relevant for her purposes. Remember that the Abstract is in many cases the only part of your text that will be read.