Are textbooks used?

Yes. For many years textbooks have been used in schools as a foundation for the body of knowledge to be covered in a course. The teachers use the pertinent parts of the textbook and supplement the textbook material as needed. The Babbage Net School makes use of textbooks rather than rewriting all the material for each course.
When a student is enrolled in a course by a school district , the district is required to provide the textbook. If the textbook is not available in the school then the district can order it from the publisher or a distributor according to their usual procedures. An individual enrolled in a course can use the links provided to order on-line or by mail.