The textbook for the course is How to Design Programs by Felleisen, Flatt, Fiedler, and Krishnamurthi, MIT Press, 2003. Make sure to use the First Edition (2003) and not the Second Edition (2018). You can read the book online or purchase it from the UW bookstore.
If the textbook and lecture slides have conflicting information, the lecture slides take precedence over the textbook. In particular, you should follow the design recipe taught in lectures, and not the textbook.