Final answer:
The purpose of a book or movie review is to evaluate the piece and provide a judgment, supported by evidence and criteria, to guide the audience's decisions.
Step-by-step explanation:
The purpose of a book or movie review is primarily to evaluate. A review offers a judgment about the piece, such as whether it achieves its goals effectively, and whether the audience should read the book or watch the film. While giving this judgment, it is crucial for reviewers to support their opinions with evidence and clear criteria to help guide readers or viewers in making their own informed decisions. This includes examining various aspects such as the cultural significance of the work, character development, and the effectiveness of its narrative or thematic elements. Reviews often employ a rating system, like stars or letter grades, to provide a quick reference for the audience.