Book reviews are one of the tools that librarians use for readers' advisory. Reviews describe the contents of books and place the works into larger literary contexts through comparisons to other works and other authors. Being able to find similar authors and books is a fundamental yet challenging aspect of readers' advisory, and literary comparisons in book reviews play an important part in this process. This paper is a content analysis from a readers' advisory perspective of the number and type of literary comparisons in library and book trade periodicals. A total of 400 fiction book reviews were gathered for the study from Booklist, Library Journal, Kirkus Reviews, and Publishers Weekly. Library Journal and Booklist were found to include the highest percentage of non-neutral comparisons to other works and other authors. It is the recommendation of the study that all of the periodicals should include more non-neutral literary comparisons. This study is valuable to librarians, who consult and write reviews, and to vendors of electronic readers' advisory databases that include full-text book reviews.