In the catalog, try a subject heading search for "author's name and criticism" without the quotes. (See for example Subject Heading: Morrison, Toni--criticism.) Books written on specific works will have their own subheading (Subject Heading Faulkner, William, 1897-1962. Light in August.).
You might also check to see if a bibliography has been published on the author you're researching. To find these, try "author's name and bibliography" as a keyword search (Faulkner, William, 1897-1962--bibliography).
Book reviews appear immediately after a book's initial publication, and anytime up to several years after that.