Columbia's essay on common app

On common app there is the following essay prompt for Columbia University:“List the titles of the required readings from courses during the school year or summer that you enjoyed most in the past year. (150 words or less)”

Do textbooks enter under the “book definition?”. I am at a small and very selective high school, at a science profile (I am an international student), and we rarely read any literature, but I read and work from a huge number of textbooks. However, I don’t think that textbooks are what admission officers want to see listed on this prompt. What should I do?

Oh, and what If I am currently reading from a book (actually working from a textbook), can I put it on the list? I mean some of the textbooks that I am using now are definitely my favorite ones. Like the Feynman Lectures on Physics and Calculus by Apostol.