"Interestingly, research suggests that instruction and practice in summarizing not only improves students' ability to summarize text, but also their overall comprehension of text content. Thus, instruction in summarization can be considered to meet dual purposes: to improve students' ability to summarize text and to improve their ability to comprehend text and recall." (Duke, N. K., & Pearson, P. D., 2002, Summarization, para. 3)
To summarize a text one must state the main concepts and important details of the original text while also mimicking the structure of the original text. This should be done in a way that creates a piece that is shorter than the original text.