Description, not a summary, of the book. Sufficient description should be given so that the reader, as he reads the review, will have some understanding of the author's thoughts. This account of the contents of a book can often be woven into the critical remarks.
Something about, not a biography of, the author. Biographical information should be relevant to the subject of the review and enhance the reader's understanding of the work under discussion.
An appraisal, preferably indirect, through description and exposition and based on the aims and purposes of the author. While a critical review is a statement of opinion, it must be a considered judgement including:
a statement of the reviewer's understanding of the author's purpose
how well the reviewer feels the author's purpose has been achieved
evidence to support the reviewer's judgement of the author' achievement.