Read the textbook chapters that you will be writing the summaries for. Read slowly for comprehension and underline, circle or highlight the most important and essential information in each chapter or section. Re-read the section over again if you want to gain a better understanding of the content or are not sure of what something means.
Divide up the information you just read and create an outline. If the chapter you read is divided up into sections with sub-headings, designate a spot on your outline for each section. Keep the sections organized in the same order that they were presented in the chapter.
Begin your summary with a sentence explaining which chapter you read, the name of the textbook the chapter appeared in and the name of the textbook's author. In the following sentence, write a brief explanation concerning what the chapter was about (for example, "In this chapter, Jones explored the fall of the Roman empire and its lasting consequences on Europe as a whole"). This thesis statement helps inform the reader what the remainder of the summary will be about.
Start a new paragraph and write about the information presented in the textbook chapter. Write in the present tense to summarize the various sections of the chapter in the order that you read them in the book, mentioning all of the pertinent information that you highlighted in step one. Keep your summary as general as possible and don't go into details that are too specific. When finished, your summary should be only a fraction as long as the material you are summarizing. A summary for a chapter that is 30 pages long might be 300-500 words while a summary for an entire textbook might be two or three pages long.