Google Books searches allow you to search within the full text of books for words or phrases.
Google Scholar searches make it easy to see where you book or article has been cited by others. And, you can search within those citations to further narrow down your results to citing works that speak to your research topic.
Use library catalogs to find books by a particular author, about a particular author, work, or topic, or search by keywords to find items that are about multiple topiocs together.
Remember, author names are inverted (Last, First) in author and subject searches.
When searching by subject, remember that subheadings can help you narrow a subject by geography, format, or subtopic. Also, "____________ in Literature" may be a handy subject heading type to keep in mind.
Sometimes it is useful to be able to search the full text of a work of literature. Often this is possible only for works no longer in copyright, which usually means written before the 1930's. For books still in copyright, partial search results may be achieved by using the Google Book Search or Amazon's Search Inside this Book program. Both allow you to search for keywords, but may only be able to tell you which page those words appear on.