How Is Writing Organized? Some nonfiction writing is organized by main idea and details. The writer begins with the main idea, or most important point about the topic. Then the writer uses details to support, or tell more about, the main idea. This helps the reader better understand the information.

Practice Together

Identify Main Idea and Details Use the information in the text above to add two more details to the chart.

Main-Idea Diagram

Try It!

Make a Main-Idea Diagram Choose another section of “The Human Machine.” Make a Main-Idea Diagram for it.

• • Figure out the topic—what the section is about.

• • Find the main idea—the most important point about that topic.

• • Write details that support the main idea.

Use your Main-Idea Diagram to tell a partner what you learned about the section you read.

A doctor listens to a patient’s breathing.