Secondary sources are works that provide commentary on historical events. They are typically written by scholars and incorporate primary source documentation in order to analyze and interpret past events. Most historians publish their work in books. So, for many topics in history, your best starting point is a good recent scholarly book.
To find historiographic essays, books, and articles, consult our Online Catalog, WorldCat and journal article databases (such as Historical Abstracts & Full Text), by using "historiography" as a Subject term.
To find book-length bibliographies on a topic in library catalogs, use the advanced search to look for "bibliography" as a Subject and your topic as a Keyword.