The ZC Horses books are non-fiction, 3-4 grade level, high interest/low vocab, ESL. The books have been tested for readability level by Renaissance. They have colorful western art illustrations. AR tests are available at the time from the author. They are very popular in schools and public libraries. Boys and girls, men and women are loving the stories The photos on the front cover are the actual horses (and dog) being read about in the books.