To find works dedicated to research on an author, do a subject search on the author's name, last name first.
A keyword search on the author's name will find these works, plus works by the author, and sections of more general works.
Online text collections deliver more detailed results than the library catalogs.
Listed here are general bibliographies and indexes. For more specific bibliographies see A Guide to Serial Bibliographies for Modern Literatures, Reference PN695 .W67 1995.
Finding criticism of specific poems or stories can sometimes be difficult. If you're stuck, try searching the bibliographies and indexes, or these print reference books can also be helpful:
Poetry Criticism
Reference PN1010 .P499
Short Story Criticism
Reference PN3373 .S386
Both are indexed in the Literary Index.
Book reviews may not be as analytical or scholarly as criticism, but reflect more immediate reaction to a book upon publication. There are some tricks to finding book reviews in the general databases. There are also indexes that list only book reviews.