Library books are cataloged by title, author, publisher, date of publication, and subject heading. A subject heading is an assigned term that tells you something of what the book is about.
For example, you might come up with the keyword "evolution". Relevant books might be cataloged with the subject headings "Evolution (biology)", or broken down into "Human evolution" or "Mammals -- Evolution" or "Vertebrates -- Evolution".
You can even click these subject headings to find more books cataloged in the same way.
What's its name? Sometimes this can be surprisingly hard to find out--but knowing the taxonomy of an organism is key to unlocking all sorts of information and research. Here are some sources to help you out.