ENG480: Studies in Literature and Folklore: Children’s Literature in Oceania: Research Tools & Strategies

OneSearch and HathiTrust are both places where you can find electronic books; when you use OneSearch, you are also searching for books within HathiTrust, but there are reasons to search in both places:

OneSearch is a "search aggregator," which means that it searches for a wide variety of resources (books, films, journal articles, audio recordings) in a wide variety of places (within Hamilton library, in various electronic databases, on the open internet and elsewhere). So the advantage of OneSearch over HathiTrust is that it searches a much broader "universe" of information than HathiTrust, and will give you access to electronic books that are not available through HathiTrust.

HathiTrust is also a type of search aggregator, but it is more limited than OneSearch, in that it only searches for electronic books (and some journal articles) and only searches for those books that are freely available from a select group of libraries that are members of HathiTrust -- so there are electronic books that you will find in OneSearch that you will not find in HathiTrust, because OneSearch also searches for books that the library pays for, and which aren't feely available through HathiTrust. On the other hand, the advantage to searching directly in HathiTrust instead of in OneSearch is that, for the books that are in HathiTrust, HathiTrust can be used to search through the entire text of all the books it holds for the keywords you are using (OneSearch does not search the full-text of electronic books, only the "metadata" -- the title, the author, the publisher and so forth).

Long story short, both OneSearch and HathiTrust are valuable tools when you're searching for books on a topic, and you will get different results searching within them.