Identify key words and concepts to find relevant results. When searching in MultiSearch, you can use the filters on the left hand side of the page to narrow your results by date, type of resource and subject heading.
Subject headings can be a way of finding more relevant resources, as these items have been 'tagged' as being about a subject, rather than just including your search terms. In MultiSearch, Google Scholar, Trove (the National Library website) and most other search tools, look for 'advanced search' to search by subject.
Here are some helpful subject terms for Threshold 5:
There's a lot of free material relating to Charles Darwin online- you can read On the Origin of Species for free at Project Gutenberg, and Darwin Online is a free Darwin archive. You can find more in the library by searching for Charles Darwin.