Summary

One part of critical reading is being certain the reader understands.

Summarizing, stating the main idea or thesis and identifying the key points of support, is one way a reader can demonstrate understanding.

A summary is an objective retelling. One rule of thumb is to ask whether the author of the original text would recognize the summary of his or her work: Did the summary get it right?

See the link Summary under Research.

Also, see Diana Hacker, A Writer's Reference, 6th ed. "A1: Writing about texts." pp. 57-66.