Is all publicity good publicity? Are all reviews—even bad ones—good for books? The answer, according to a new study [pdf] by the journal Marketing Science, depends on whether the writer is well known or unknown. The study examined the impact of a New York Times review on the sales of more than 200 hardcover titles. For books by established writers, a negative review led to a 15% decrease in sales. For unknown authors, a negative review increased sales by a healthy 45%.