Companions and handbooks are authoritative guides to a topic compiled by leading scholars. These guides often serve as valuable introductions to a topic.
Cambridge Companions are a series of authoritative guides, written by leading experts, offering lively, accessible introductions to major writers, artists, philosophers, topics, and periods.
Contains the complete texts of over 250 volumes published since the 1960's in this prestigious series of authoritative works on major historical topics. Several series are still active and new volumes will be added to the database as published, as will any new series when they begin.
This is almost certainly the most comprehensive database of Congressional publications, some dating back as far as the late 1700's. Includes the complete texts of hearings and most other documents. An interesting sub-set of the database provides legislative histories. (Law Library subscription.)
Slavery and Anti-Slavery: A Transnational Archive is devoted to the study and understanding of the history of slavery in America and the rest of the world from the 17th century to the late 19th century. Archival collections were sourced from more than 60 libraries at institutions such as the Amistad Research Center, Bibliothèque nationale de France, the National Archives, Oberlin College, Oxford University, the Schomburg Center for Research in Black Culture, and Yale University…
Published in 2006 as a five-volume set, HSUS is a database of over 37,000 data series (statistical categories) from U.S. and Colonial history. The database also contains extensive essays on the measurements of U.S. history. Data are available as published tables, spreadsheet files (Excel), PDF documents, and graphs or charts.
Described as "the world's most comprehensive collection of dissertations and theses," this database contains over 2.7 million citations to dissertations and theses from around the world, dating back to 1861. About 1.2 million items are provided in full-text (PDF) form.
Google Scholar is a freely available index. You might use it as an alternative to some of the other resources listed in this guide. However, practically any information in Google Scholar will also be found in the other resources. Plus, the other resources are likely to turn up additional resources.
Tracing the citations through Google Scholar can reveal interesting threads of research. It's actually an approach that I use quite often, but only after I have identified a handful of key articles or books on my topic.
Example: if you using the book Master of the Mountain: Thomas Jefferson and his slaves [Wiencek, Henry. Master of the mountain: Thomas Jefferson and his slaves. Macmillan, 2012], then you can find what articles and books have cited that book since it was published. You'll find pointers to 65 works. Some of those may be relevant, some may not. There are many different reasons why an author cites another work. So you need to use your judgment as to whether the citation is relevant, which means you're likely need to look at how the cited work is used in the referring text.
But, at times, citation tracing can be a useful and fun mechanism for filtering information and entering the scholarly conversation taking place on a topic.
When searching the Web, be very careful when searching for material about Thomas Jefferson. You will find a lot of false hits. For example, if you search "Thomas Jefferson", then you will get a lot of search results about "Thomas Jefferson University" or other facilities named for Jefferson. Because of the overwhelming nature of material containing the name Jefferson, you should not depend upon Google search results. Better to spend your time on the scholarly resources indicated in this guide.