To start a book review, you can begin by providing some background information about the book, such as the title, author, genre, and publication date. You can also give a brief summary of the plot or main themes of the book to provide context for your review. Additionally, you may want to mention your overall impression of the book, such as whether you found it engaging, thought-provoking, or well-written. Finally, you can introduce the main points you will be discussing in your review, such as the characters, writing style, and themes, to give readers an idea of what to expect.