It might help to rephrase your topic as a question. Think of broader and narrower terms e.g. water pollution, streams, freshwater. Encyclopedias Dictionaries Bibliographies Textbooks Use the Library Catalogue to identify encyclopedias, bibliographies and dictionaries for specific subjects.
Textbooks often contain a chapter which gives a good introduction to a topic.
In the above example look for a textbook on environmental pollution. See How to Use the Catalogue if you require further help. Gathering Data You need to gather data from different sources including books, periodical articles, the Internet and Online Databases. Some resources are only available in the library while others are available electronically from your home. Publishers web sites - compiled by Birkbeck College Library.