Reference resources are a great place to begin your research. They can help you define terms as well as to find basic information about a topic, a chronicle of its history, theories, key people and sometimes a bibliography of additional sources.
There are many different types of reference sources, which include dictionaries, encyclopedias, thesauri, bibliographies, handbooks, style manuals to name a few.
Album of American History
E178 .A2 A (5 volumes; Stauffer – Books)
Atlas of the Civil War
G1201 .S5A85 1994 (Maps)
A Companion to American Cultural History
Also E169.1 .C684 2008
Encyclopedia of American History
REF E174 .E53 2003
Historical Times Illustrated Encyclopedia of the Civil War
REF E468 .H57 1986