A book review is a form of literary criticism in which a book is analyzed based on content, style, and merit. It is often carried out in periodicals, as school work, or on the internet. Reviews are also often published in magazines and newspapers. Its length may vary from a single paragraph to a substantial essay. Such a review often contains evaluations of the book on the basis of personal taste. Reviewers, in literary periodicals, often 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. At the other end of the spectrum, some book reviews resemble simple plot summaries.