Should Textbook chapters Contain a "Summary" Section
I've been struggling with this for months.  I think I've found the answer to my implied question in the words of another textbook author, Ken Saladin.
&quot;...tell students what they should know about, but not what to know about it.&quot;
Following Saladin's advice, I've re-titled the summary sections Summary of Learning Objectives. Each summary section now starts with the following:

This section of the chapter tells you the things you should know about, but not what you should know about them. To test your knowledge, discuss the following concepts and topics with a study partner or in writing, ideally from memory.

That's nearly a direct quote from Saladin's suggestion.  I hope the first sentence will dissuade students from thinking they can read the summaries only.
I suggest those interested in the question read Dr. Saladin's entire, but short, blog post: https://blog.taaonline.net/2020/02/textbook-pedagogy-improving-chapter-summaries-encourages-collaborative-learning/