Justifying an Evaluation. Defend with evidence your opinion about a non-fiction books. Errors made by students: a) Writing about fiction. For example, a realistic novel is still fiction. Publishers and bookstores don’t keep it a secret what is fiction or non-fiction. If you can’t tell, you have reading problems. b) Not forming or defending a thesis, just summarizing the book. c) Making your essay about the subject of the book you’re analyzing, and not the book. Example: I read a book review by a critic who loves the work of Beat writer William Burroughs, but hated the biography of Burroughs he reviewed because it was a bad book.