Not sure what topic you want to write about?
Have a topic but need background information?
The sources listed here will provide background information, key terms, important themes and individuals in the field, and provide keywords for further searching in catalogs and databases.
Bibliographies (list of references/sources) are usually included that will help you identify important primary and secondary works in your subject area.
"Research can be difficult, but you don't have to start from scratch if you follow the clues left by scholars who have gone before you!"
See the section: Following Those Citations! for instructions on how to locate the references you find.
In addition, as you conduct your research, you will need to make note of those additional resources (book, book chapter, journal article) you identify in the bibliographies, references, notes and footnotes of the sources you are using. The reason for this? Because this is one of the best ways to further your research.
Keep track of your references!
Use a Bibliographic Management Tool
The Oxford Handbook of U. S. Environmental Policy by 
Encyclopedia of the U. S. Government and the Environment by 
Encyclopedia of Sustainability by 
International Encyclopedia of Environmental Politics by 