The following guideline comes from Mary Lynn Rampolla, A Pocket Guide to Writing in History:

Book Review Guidelines
Guidelines for Book Reviews
Each review should be from 500 to 750 words in length (two to three pages, double-spaced, with one-inch margins all around).
The following guideline comes from Mary Lynn Rampolla, A Pocket Guide to Writing in History:
A book review is not the same thing as a book report, which simply summarizes the content of a book. When writing a book review, you not only report on the content of the book but also assess its strengths and weaknesses. Students sometimes imagine themselves unqualified to write a book review; after all, the author of the book is a professional historian. However, even if you cannot write from the same level of experience and knowledge as the author, you can write an effective review if you understand what the assignment requires.
In writing a review you do not just relate whether or not you liked the book; you also tell your reader why you liked or disliked it. It is not enough to say, “This book is interesting”; you need to explain why it is interesting. Similarly, it is not enough to report that you disliked a book; you must explain your reaction. Did you find the book unconvincing because the author did not supply enough evidence to support his or her assertions? Or did you disagree with the book’s underlying assumptions?
To understand your own reaction to the book, you need to read it carefully and critically.
As a critical reader, you are not passive; you should ask questions of the book and note reactions as you read. Your book review then discusses those questions and reactions. Though there is no “correct” way to structure a review, the following is one possible approach.
Summarize the book and relate the author’s main point or thesis. (Somewhere early in the essay, identify the author briefly.)
Describe the author’s viewpoint and purpose for writing; note any aspects of the author’s background that are important for understanding the book.
Note the most important evidence the author presents to support his or her thesis.
Evaluate the author’s use of evidence, and describe how he or she deals with counter evidence. Is the book’s argument persuasive?
Compare this book with other books or articles you may have read on the same subject.
Conclude with a final evaluation of the book. You might discuss who would find this book useful and why.
Note: “Critical” does not mean negative. If a book is well written and presents an original thesis supported by convincing evidence, say so. A good book review does not have to be negative; it does have to be fair and analytical.
As a formal writing assignment:
You must include page numbers; and you must remember to indent paragraphs.
Do not use contractions.
Avoid euphemisms: i.e., people “die,” they do not “pass away.”
Strive for precision and economy of language. There are no such things as “combat situations” or “crisis situations.” People are engaged in combat; they may also be caught up in a crisis or in crises. Things can’t be “totally destroyed.” They can only be destroyed; otherwise, they are damaged. It would seem silly to suggest that something is “partially damaged.” Remember to check the spelling in your review.