Critical book reviews include an analysis of the work, but are are authored for a general audience not necessarily an academic one. The authors of critical book reviews are often experts in their respective fields, but not always academics or scholars, and their reviews are lengthier than general interest (popular) reviews. These reviews can be used to help determine if a an individual or a larger entity, such as a library or a bookstore, want to purchase the media in question, or for determining if a book is relevant to one's research.