Fourth graders require more scaffolding with summarizing, but we introduce the formula of main idea + important details to help prepare them for more complex summarizing in the fifth grade.
I began the lesson with the following anchor chart. (Students also glued a copy into their reader's notebooks.)
For this lesson, I used a book about the Wright brothers. They are local legends around here. Also, students have a big biography assignment due in their classrooms this month, so this provided a nice connection. Students independently read the introduction of the book. Then we identified the main idea together, and students wrote this main idea on a post-it. (labeled main idea.)
I also added the main idea to our anchor chart.
The book was broken up nicely into sections with headings. Students independently read one section at a time and then we determined what the important detail(s) were. We then wrote these details on post-its and stuck them to our books.
Also, to continue reviewing nonfiction text features, we completed a text feature "scavenger hunt" with the text. Students had to find the correct page number for each text feature. The "scavenger hunt" form can be found at: http://www.teacherspayteachers.com/Product/Non-Fiction-Feature-Scavenger-Hunt.