Q. I have been using the Robert Marzano, "What Works in Schools" ebook since the beginning of the semester for my TED 4000 class, and up until last

Because of licensing issues, e-book access to textbooks has been disappearing since last Spring.  The attached file is a part of an internal e-mail dealing with this issue.  It appears that What Works in Schools is one of the books which had "fallen through the cracks" up to this point.  If the book is required for your class, you should be able to purchase a copy at the bookstore.