Encyclopedias/ reference resources are meant to offer an overview of a particular topic: background information, essays by specialists, and resources recommended for deeper research. 

 Gale Virtual Reference Library:
A database of electronic reference sources. Try a keyword search for descent of man , Darwin, frontier and Turner, technology and Frankenstein,etc. to get an overview of your topic.

The Cal State LA Library also offers many individual electronic reference resources, such as...

• Brittanica Online
  A general encyclopedia, with entries on interdisciplinary topics.
• Dictionary of Literary Biography
  Biographical and critical essays on influential literary figures.
• Cambridge Dictionary of Human Biology and Evolution
  Defines and elaborates on important terms in biology and evolution.
• Encyclopedia of Race, Ethnicity, and Society
  Search for entries by topic, or browse the Readers Guide for "Concepts and Theories" such as assimilation, and colonialism, and cultural relativism.
• Encyclopedia of Gender and Society
  Search for entries by topic, or browse the Readers Guide.
• Stanford Encyclopedia of Philosophy
  Coverage of philosophic topics.
• Blackwell Encyclopedia of Sociology Online
  Contains specially-commissioned entries on sociological theories and research.
• Oxford English Dictionary
  Provides word definitions and histories.