A book review is a form of literary criticism in which a book is analyzed based on content, style, and merit. A book review can be a primary source opinion piece, summary review or scholarly review. Books can be reviewed for printed periodicals, magazines and newspapers, as school work, or for book web sites on the Internet. A book review's length may vary from a single paragraph to a substantial essays. Such a review may evaluate the book on the basis of personal taste. Reviewers may use the occasion of a book review for a display of learning or to promulgate their own ideas on the topic of a fiction or non-fiction work.