Question: What value lies in a reference work? Why should you bother to consult these books?
Answer: Reference books help create a framework around your topic. They can help guide you in asking the right questions. Reference books can help researchers become more efficient database searchers - in formulating which keywords (or search terms) to use. Scholarly reference books also contain bibliographies (!!) - a listing of some of the most respected secondary and most useful primary sources on a topic. In a nutshell.... reference books are a great way to begin your research.
Subject headings to explore:
Encyclopedia of Latin American history and culture by 
The Cambridge companion to modern Latin American culture by 
Latin American civilization : history and society, 1492 to the present by 
Historical atlas of Central America by Statistical yearbook for Latin America and the Caribbean 2002